old_contents: """Python implementation of Z85 85-bit encoding
  
  Z85 encoding is a plaintext encoding for a bytestring interpreted as 32bit integers.
  Since the chunks are 32bit, a bytestring must be a multiple of 4 bytes.
  See ZMQ RFC 32 for details.
  
  
  """
  
  # Copyright (C) PyZMQ Developers
  # Distributed under the terms of the Modified BSD License.
  
  import sys
  import struct
  
  PY3 = sys.version_info[0] >= 3
  # Z85CHARS is the base 85 symbol table
  Z85CHARS = b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#"
  # Z85MAP maps integers in [0,84] to the appropriate character in Z85CHARS
  Z85MAP = dict([(c, idx) for idx, c in enumerate(Z85CHARS)])
  
  _85s = [ 85**i for i in range(5) ][::-1]
  
  def encode(rawbytes):
      """encode raw bytes into Z85"""
      # Accepts only byte arrays bounded to 4 bytes
      if len(rawbytes) % 4:
          raise ValueError("length must be multiple of 4, not %i" % len(rawbytes))
      
      nvalues = len(rawbytes) / 4
      
      values = struct.unpack('>%dI' % nvalues, rawbytes)
      encoded = []
      for v in values:
          for offset in _85s:
              encoded.append(Z85CHARS[(v // offset) % 85])
      
      # In Python 3, encoded is a list of integers (obviously?!)
      if PY3:
          return bytes(encoded)
      else:
          return b''.join(encoded)
  
  def decode(z85bytes):
      """decode Z85 bytes to raw bytes"""
      if PY3 and isinstance(z85bytes, str):
          z85bytes = z85bytes.encode('ascii')
  
      if len(z85bytes) % 5:
          raise ValueError("Z85 length must be multiple of 5, not %i" % len(z85bytes))
      
      nvalues = len(z85bytes) / 5
      values = []
      for i in range(0, len(z85bytes), 5):
          value = 0
          for j, offset in enumerate(_85s):
              value += Z85MAP[z85bytes[i+j]] * offset
          values.append(value)
      return struct.pack('>%dI' % nvalues, *values)
  
new_contents: """Python implementation of Z85 85-bit encoding
  
  Z85 encoding is a plaintext encoding for a bytestring interpreted as 32bit integers.
  Since the chunks are 32bit, a bytestring must be a multiple of 4 bytes.
  See ZMQ RFC 32 for details.
  
  
  """
  
  # Copyright (C) PyZMQ Developers
  # Distributed under the terms of the Modified BSD License.
  
  import sys
  import struct
  
  PY3 = sys.version_info[0] >= 3
  # Z85CHARS is the base 85 symbol table
  Z85CHARS = b"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#"
  # Z85MAP maps integers in [0,84] to the appropriate character in Z85CHARS
  Z85MAP = dict([(c, idx) for idx, c in enumerate(Z85CHARS)])
  
  _85s = [ 85**i for i in range(5) ][::-1]
  
  def encode(rawbytes):
      """encode raw bytes into Z85"""
      # Accepts only byte arrays bounded to 4 bytes
      if len(rawbytes) % 4:
          raise ValueError("length must be multiple of 4, not %i" % len(rawbytes))
      
      nvalues = len(rawbytes) / 4
      
      values = struct.unpack('>%dI' % nvalues, rawbytes)
      encoded = []
      for v in values:
          for offset in _85s:
              encoded.append(Z85CHARS[(v // offset) % 85])
      
      # In Python 3, encoded is a list of integers (obviously?!)
      if PY3:
          return bytes(encoded)
      else:
          return b''.join(encoded)
  
  def decode(z85bytes):
      """decode Z85 bytes to raw bytes"""
      if PY3 and isinstance(z85bytes, str):
          raise TypeError("Unicode-objects must be encoded to bytes")
  
      if len(z85bytes) % 5:
          raise ValueError("Z85 length must be multiple of 5, not %i" % len(z85bytes))
      
      nvalues = len(z85bytes) / 5
      values = []
      for i in range(0, len(z85bytes), 5):
          value = 0
          for j, offset in enumerate(_85s):
              value += Z85MAP[z85bytes[i+j]] * offset
          values.append(value)
      return struct.pack('>%dI' % nvalues, *values)
  
subject: Raise TypeError instead of encoding