class_docstr: Connect4 Game class implementing the alpha-zero-general Game interface.
  
  Use 1 for player1 and -1 for player2.
code: def __init__(
      self, height=None, width=None, win_length=None, np_pieces=None
  ):
      self._base_board = Board(height, width, win_length, np_pieces)
  
imports: import numpy
  from collections import namedtuple
label_desc: Use image node_id 1 to create a new Connect4Game object from inherited base classes: object with example: obj = Connect4Game(height, width, win_length, np_pieces)