old_contents: __all__ = ['popCount']
  
  
  def popCount(v):
      """Return number of 1 bits (population count) of an integer.
  
      If the integer is negative, the number of 1 bits in the
      twos-complement representation of the integer is returned. i.e.
      ``popCount(-30) == 28`` because -30 is::
  
          1111 1111 1111 1111 1111 1111 1110 0010
  
      Uses the algorithm from `HAKMEM item 169 <https://www.inwap.com/pdp10/hbaker/hakmem/hacks.html#item169>`_.
  
      Args:
          v (int): Value to count.
  
      Returns:
          Number of 1 bits in the binary representation of ``v``.
      """
  
      if v > 0xFFFFFFFF:
          return popCount(v >> 32) + popCount(v & 0xFFFFFFFF)
  
      # HACKMEM 169
      y = (v >> 1) & 0xDB6DB6DB
      y = v - y - ((y >> 1) & 0xDB6DB6DB)
      return (((y + (y >> 3)) & 0xC71C71C7) % 0x3F)
  
new_contents: __all__ = ['popCount']
  
  
  try:
      bit_count = int.bit_count
  except AttributeError:
      def bit_count(v):
          return bin(v).count('1')
  
  """Return number of 1 bits (population count) of the absolute value of an integer.
  
  See https://docs.python.org/3.10/library/stdtypes.html#int.bit_count
  """
  popCount = bit_count
  
subject: Consolidate bit_count / popCount methods