old_contents: #!/usr/bin/env python3
  #
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Big number routines.
  
  Functions for converting numbers to MPI format and Bitcoin-specific little
  endian format.
  
  This file is copied from python-bitcoinlib.
  """
  def bn2bin(v):
      """Convert a number to a byte array."""
      s = bytearray()
      bytes_len = (v.bit_length() + 7) // 8
      for i in range(bytes_len, 0, -1):
          s.append((v >> ((i - 1) * 8)) & 0xff)
      return s
  
  def bn2mpi(v):
      """Convert number to MPI format, without the sign byte."""
      have_ext = False
      if v.bit_length() > 0:
          have_ext = (v.bit_length() & 0x07) == 0
  
      neg = False
      if v < 0:
          neg = True
          v = -v
  
      ext = bytearray()
      if have_ext:
          ext.append(0)
      v_bin = bn2bin(v)
      if neg:
          if have_ext:
              ext[0] |= 0x80
          else:
              v_bin[0] |= 0x80
      return ext + v_bin
  
  def bn2vch(v):
      """Convert number to bitcoin-specific little endian format."""
      return bytes(reversed(bn2mpi(v)))
  
new_contents: #!/usr/bin/env python3
  #
  # Distributed under the MIT software license, see the accompanying
  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  """Big number routines.
  
  Functions for converting numbers to MPI format and Bitcoin-specific little
  endian format.
  
  This file is copied from python-bitcoinlib.
  """
  def bn2mpi(v):
      """Convert number to MPI format, without the sign byte."""
      # The top bit is used to indicate the sign of the number. If there
      # isn't a spare bit in the bit length, add an extension byte.
      have_ext = False
      ext = bytearray()
      if v.bit_length() > 0:
          have_ext = (v.bit_length() & 0x07) == 0
          ext.append(0)
  
      # Is the number negative?
      neg = False
      if v < 0:
          neg = True
          v = -v
  
      # Convert the int to bytes
      v_bin = bytearray()
      bytes_len = (v.bit_length() + 7) // 8
      for i in range(bytes_len, 0, -1):
          v_bin.append((v >> ((i - 1) * 8)) & 0xff)
  
      # Add the sign bit if necessary
      if neg:
          if have_ext:
              ext[0] |= 0x80
          else:
              v_bin[0] |= 0x80
      return ext + v_bin
  
  def bn2vch(v):
      """Convert number to bitcoin-specific little endian format."""
      return bytes(reversed(bn2mpi(v)))
  
subject: remove bn2bin()