docs: def parse_cdhit_clstr_file(lines):
      """Returns a list of list of sequence ids representing clusters"""
      clusters = []
      curr_cluster = []
  
      for l in lines:
          if l.startswith('>Cluster'):
              if not curr_cluster:
                  continue
              clusters.append(curr_cluster)
              curr_cluster = []
          else:
              curr_cluster.append(clean_cluster_seq_id(l.split()[2]))
  
      if curr_cluster:
          clusters.append(curr_cluster)
  
      return clusters