def implemented(module, func):
    """
  Function to check if a function func exists in module.

  Arguments
  ---------
  module : any
           The module where the presence of function needs
           to be checked.
  func : str
         The name of the function in str whose presence 
         needs to be confirmed.

  Raises
  ------
  NotImplementedError : If the function is not present in module.
  """
    imp = getattr(module, func)
    if not callable(imp):
        raise NotImplementedError
