docs: def get_pairs(db, collection, experiment=None, subject=None, group=None, name='seq_id',
      delim=None, delim_occurance=1, pairs_only=False, h_selection_func=None, l_selection_func=None):
      '''
      Gets sequences and assigns them to the appropriate mAb pair, based on the sequence name.
  
      Inputs:
  
      ::db:: is a pymongo database connection object
      ::collection:: is the collection name, as a string
      If ::subject:: is provided, only sequences with a 'subject' field matching ::subject:: will
          be included. ::subject:: can be either a single subject (as a string) or an iterable
          (list or tuple) of subject strings.
      If ::group:: is provided, only sequences with a 'group' field matching ::group:: will
          be included. ::group:: can be either a single group (as a string) or an iterable
          (list or tuple) of group strings.
      ::name:: is the dict key of the field to be used to group the sequences into pairs.
          Default is 'seq_id'
      ::delim:: is an optional delimiter used to truncate the contents of the ::name:: field.
          Default is None, which results in no name truncation.
      ::delim_occurance:: is the occurance of the delimiter at which to trim. Trimming is performed
          as delim.join(name.split(delim)[:delim_occurance]), so setting delim_occurance to -1 will
          trucate after the last occurance of delim. Default is 1.
      ::pairs_only:: setting to True results in only truly paired sequences (pair.is_pair == True)
          will be returned. Default is False.
  
      Returns a list of Pair objects, one for each mAb pair.
      '''
      match = {}
      if subject is not None:
          if type(subject) in (list, tuple):
              match['subject'] = {'$in': subject}
          elif type(subject) in STR_TYPES:
              match['subject'] = subject
      if group is not None:
          if type(group) in (list, tuple):
              match['group'] = {'$in': group}
          elif type(group) in STR_TYPES:
              match['group'] = group
      if experiment is not None:
          if type(experiment) in (list, tuple):
              match['experiment'] = {'$in': experiment}
          elif type(experiment) in STR_TYPES:
              match['experiment'] = experiment
      seqs = list(db[collection].find(match))
      return assign_pairs(seqs, name=name, delim=delim,
          delim_occurance=delim_occurance, pairs_only=pairs_only,
          h_selection_func=h_selection_func, l_selection_func=l_selection_func)