code: def get_boundaries(self, filter_type, value):
          
  
          assert filter_type in self.handled_suffixes
  
          start = '-inf'
          end = '+inf'
          exclude = None
  
          if filter_type in (None, 'eq'):
              # only one score
              start = end = value
  
          elif filter_type == 'gt':
              start = '(%s' % value
  
          elif filter_type == 'gte':
              start = value
  
          elif filter_type == 'lt':
              end = '(%s' % value
  
          elif filter_type == 'lte':
              end = value
  
          return start, end, exclude
docs: Compute the boundaries to pass to the sorted-set command depending of the filter type
  
          The third return value, ``exclude`` is always ``None`` because we can easily restrict the
          score to filter on in the sorted-set.
  
          For the parameters, see BaseRangeIndex.store
  
          Notes
          -----
          For zrangebyscore:
          - `(` means "not included"
          - `-inf` alone means "from the very beginning"
          - `+inf` alone means "to the very end"