Testing dataframe with extra attributes

test_dataframe.py

import pandas as pd
class MyDF(pd.DataFrame):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.definition = 'my_definition'

my_df = MyDF()
my_df.__dict__ = df.__dict__.copy()
print(len(my_df))
print(my_df.definition)
save_variables_to_pickle(my_df, 'my_df.pkl')

my_df2 = load_variables_from_pickle('my_df.pkl')

print(len(my_df2))
print(my_df2.definition)