code: def binary_check(classes):
      """
      Check if the problem is a binary classification.
  
      :param classes: confusion matrix classes
      :type classes: list
      :return: is_binary as bool
      """
      num_classes = len(classes)
      is_binary = False
      if num_classes == 2:
          is_binary = True
      return is_binary
  
imports: from __future__ import division
  import sys
  import math
  import numpy
  import re
  from .pycm_param import *
  from .pycm_error import pycmMatrixError
  from warnings import warn
  from functools import wraps
label_desc: Use image node_id 19 for calling a global function with example usage: binary_check(classes) and returns: is_binary