docs: def convert_coordinate(self, chromosome, position, strand='+'):
          '''
          Returns a *list* of possible conversions for a given chromosome position.
          The list may be empty (no conversion), have a single element (unique conversion), or several elements (position mapped to several chains).
          The list contains tuples (target_chromosome, target_position, target_strand, conversion_chain_score),
          where conversion_chain_score is the "alignment score" field specified at the chain used to perform conversion. If there
          are several possible conversions, they are sorted by decreasing conversion_chain_score.
          
          IF chromosome is completely unknown to the LiftOver, None is returned.
          
          Note that coordinates are 0-based, and even at negative strand are relative to the beginning of the genome.
          I.e. position 0 strand + is the first position of the genome. Position 0 strand - is also the first position of the genome 
          (and the last position of reverse-complemented genome).
          '''
          query_results = self.chain_file.query(chromosome, position)
          if query_results is None:
              return None
          else:
              # query_results contains intervals which contain the query point. We simply have to remap to corresponding targets.
              results = []
              for (source_start, source_end, data) in query_results:
                  target_start, target_end, chain = data
                  result_position = target_start + (position - source_start)
                  if chain.target_strand == '-':
                      result_position = chain.target_size - 1 - result_position
                  result_strand = chain.target_strand if strand == '+' else ('+' if chain.target_strand == '-' else '-')
                  results.append((chain.target_name, result_position, result_strand, chain.score))
              #if len(results) > 1:
              results.sort(key=lambda x: x[3], reverse=True)
              return results