230 lines
8.4 KiB
Python
230 lines
8.4 KiB
Python
# Author: insin
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# Site: http://www.djangosnippets.org/snippets/308/
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from django.core.paginator import InvalidPage, EmptyPage
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from collections import defaultdict
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from unicodedata import normalize
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import locale
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ORDER_VAR = 'o'
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ORDER_TYPE_VAR = 'ot'
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def first_letter(text):
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"""
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Text should be a unicode string. Returns first letter.
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"""
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if len(text) > 0:
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letter = normalize('NFKC', text)[0].upper()
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(lang_country, modifier ) = locale.getlocale()
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if lang_country == "sv_SE" and letter in [u'W', u'V']:
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letter = u'V,W'
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return letter
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else:
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return u'?'
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class SortHeaders:
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"""
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Handles generation of an argument for the Django ORM's
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``order_by`` method and generation of table headers which reflect
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the currently selected sort, based on defined table headers with
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matching sort criteria.
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Based in part on the Django Admin application's ``ChangeList``
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functionality.
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"""
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def __init__(self, request, headers, default_order_field=None,
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default_order_type='asc', additional_params=None):
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"""
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request
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The request currently being processed - the current sort
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order field and type are determined based on GET
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parameters.
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headers
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A list of two-tuples of header text and matching ordering
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criteria for use with the Django ORM's ``order_by``
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method. A criterion of ``None`` indicates that a header
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is not sortable.
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default_order_field
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The index of the header definition to be used for default
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ordering and when an invalid or non-sortable header is
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specified in GET parameters. If not specified, the index
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of the first sortable header will be used.
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default_order_type
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The default type of ordering used - must be one of
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``'asc`` or ``'desc'``.
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additional_params:
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Query parameters which should always appear in sort links,
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specified as a dictionary mapping parameter names to
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values. For example, this might contain the current page
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number if you're sorting a paginated list of items.
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"""
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if default_order_field is None:
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for i, (header, query_lookup) in enumerate(headers):
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if query_lookup is not None:
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default_order_field = i
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break
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if default_order_field is None:
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raise AttributeError('No default_order_field was specified and none of the header definitions given were sortable.')
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if default_order_type not in ('asc', 'desc'):
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raise AttributeError('If given, default_order_type must be one of \'asc\' or \'desc\'.')
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if additional_params is None: additional_params = {}
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self.header_defs = headers
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self.additional_params = additional_params
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self.order_field, self.order_type = default_order_field, default_order_type
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# Determine order field and order type for the current request
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params = dict(request.GET.items())
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if ORDER_VAR in params:
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try:
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new_order_field = int(params[ORDER_VAR])
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if headers[new_order_field][1] is not None:
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self.order_field = new_order_field
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except (IndexError, ValueError):
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pass # Use the default
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if ORDER_TYPE_VAR in params and params[ORDER_TYPE_VAR] in ('asc', 'desc'):
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self.order_type = params[ORDER_TYPE_VAR]
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def headers(self):
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"""
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Generates dicts containing header and sort link details for
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all defined headers.
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"""
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for i, (header, order_criterion) in enumerate(self.header_defs):
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th_classes = []
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new_order_type = 'asc'
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if i == self.order_field:
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th_classes.append('sorted %sending' % self.order_type)
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new_order_type = {'asc': 'desc', 'desc': 'asc'}[self.order_type]
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yield {
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'text': header,
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'sortable': order_criterion is not None,
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'url': self.get_query_string({ORDER_VAR: i, ORDER_TYPE_VAR: new_order_type}),
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'class_attr': (th_classes and ' class="%s"' % ' '.join(th_classes) or ''),
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}
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def get_query_string(self, params):
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"""
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Creates a query string from the given dictionary of
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parameters, including any additonal parameters which should
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always be present.
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"""
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params.update(self.additional_params)
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return '?%s' % '&'.join(['%s=%s' % (param, value) \
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for param, value in params.items()])
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def get_order_by(self):
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"""
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Creates an ordering criterion based on the current order
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field and order type, for use with the Django ORM's
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``order_by`` method.
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"""
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return '%s%s' % (
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self.order_type == 'desc' and '-' or '',
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self.header_defs[self.order_field][1],
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)
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class NamePaginator(object):
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"""Pagination for string-based objects"""
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def __init__(self, object_list, on=None, per_page=25):
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self.object_list = object_list
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self.count = len(object_list)
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self.pages = []
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# chunk up the objects so we don't need to iterate over the whole list for each letter
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chunks = defaultdict(list)
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for obj in self.object_list:
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if on:
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obj_str = unicode(getattr(obj, on))
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else:
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obj_str = unicode(obj)
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letter = first_letter(obj_str[0])
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chunks[letter].append(obj)
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# the process for assigning objects to each page
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current_page = NamePage(self)
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for letter in string.ascii_uppercase:
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if letter not in chunks:
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current_page.add([], letter)
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continue
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sub_list = chunks[letter] # the items in object_list starting with this letter
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new_page_count = len(sub_list) + current_page.count
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# first, check to see if sub_list will fit or it needs to go onto a new page.
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# if assigning this list will cause the page to overflow...
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# and an underflow is closer to per_page than an overflow...
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# and the page isn't empty (which means len(sub_list) > per_page)...
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if (new_page_count > per_page and
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abs(per_page - current_page.count) < abs(per_page - new_page_count) and
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current_page.count > 0):
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# make a new page
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self.pages.append(current_page)
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current_page = NamePage(self)
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current_page.add(sub_list, letter)
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# if we finished the for loop with a page that isn't empty, add it
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if current_page.count > 0: self.pages.append(current_page)
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def page(self, num):
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"""Returns a Page object for the given 1-based page number."""
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if len(self.pages) == 0:
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return None
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elif num > 0 and num <= len(self.pages):
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return self.pages[num-1]
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else:
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raise InvalidPage
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@property
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def num_pages(self):
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"""Returns the total number of pages"""
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return len(self.pages)
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class NamePage(object):
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def __init__(self, paginator):
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self.paginator = paginator
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self.object_list = []
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self.letters = []
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@property
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def count(self):
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return len(self.object_list)
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@property
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def start_letter(self):
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if len(self.letters) > 0:
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self.letters.sort(key=locale.strxfrm)
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return first_letter(self.letters)
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else: return None
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@property
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def end_letter(self):
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if len(self.letters) > 0:
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self.letters.sort(key=locale.strxfrm)
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return self.letters[-1]
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else: return None
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@property
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def number(self):
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return self.paginator.pages.index(self) + 1
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def add(self, new_list, letter=None):
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if len(new_list) > 0: self.object_list = self.object_list + new_list
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if letter: self.letters.append(letter)
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def __unicode__(self):
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if self.start_letter == self.end_letter:
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return self.start_letter
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else:
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return u'%c-%c' % (self.start_letter, self.end_letter)
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