code: def convert_from_bytes_if_necessary(prefix, suffix):
      
      if isinstance(prefix, bytes):
          prefix = prefix.decode('ascii')
  
      if isinstance(suffix, bytes):
          suffix = suffix.decode('ascii')
  
      return prefix, suffix
docs: Depending on how we extract data from pysam we may end up with either
      a string or a byte array of nucleotides. For consistency and simplicity,
      we want to only use strings in the rest of our code.