code: def _serialize_linear_biases(linear, nodelist):
      
      linear_bytes = struct.pack('<' + 'd' * len(linear), *[linear[i] for i in nodelist])
      return base64.b64encode(linear_bytes).decode('utf-8')
docs: Serializes the linear biases.
  
      Args:
          linear: a interable object where linear[v] is the bias
              associated with v.
          nodelist (list): an ordered iterable containing the nodes.
  
      Returns:
          str: base 64 encoded string of little endian 8 byte floats,
              one for each of the biases in linear. Ordered according
              to nodelist.
  
      Examples:
          >>> _serialize_linear_biases({1: -1, 2: 1, 3: 0}, [1, 2, 3])
          'AAAAAAAA8L8AAAAAAADwPwAAAAAAAAAA'
          >>> _serialize_linear_biases({1: -1, 2: 1, 3: 0}, [3, 2, 1])
          'AAAAAAAAAAAAAAAAAADwPwAAAAAAAPC/'