May i get help see how am i going,

[AhmadMWaddah]

when i try this i could not access class method from other class.
example : i need the method Mean() to use it in class of Variance,
could not do it, i got the methods undefined.

Class Data_variance:
   def data_variance(data_values, mean_of_data):
    """
    Getting The Variance Number For Data.
    :param data_values: Set Of Data
    :param mean_of_data: Mean Of Data From Previous Function.
    :return: Variance Of Data.
    """
    starter_counter = 0
    for data_cells in data_values:
        starter_counter += (data_cells - mean_of_data) ** 2
    return starter_counter / len(data_values)