course_project/data_persistence.py

import pickle
import os

DATABASE_LOCATION = "course_project/database/"
MOVIES_BK_FILE_LOCATION = DATABASE_LOCATION + "provisional_database_simulation.pkl"
MOVIES_BK_FILE_TRANSFORMED_LOCATION = DATABASE_LOCATION + "provisional_database_transformed.pkl"

def save_pickle(df, filename):
    with open(filename, 'wb') as f:
            pickle.dump(df, f)

def read_pickle(filename):
    with open(filename, 'rb') as f:
        df = pickle.load(f)
    return df

def save_db(series_to_store):
    save_pickle(series_to_store, MOVIES_BK_FILE_LOCATION)

def get_db():
    if os.path.exists(MOVIES_BK_FILE_LOCATION):
        return read_pickle(MOVIES_BK_FILE_LOCATION)
    else:
        return None

def save_transformed_db(series_to_store):
    save_pickle(series_to_store, MOVIES_BK_FILE_TRANSFORMED_LOCATION)

def get_transformed_db():
    if os.path.exists(MOVIES_BK_FILE_TRANSFORMED_LOCATION):
        return read_pickle(MOVIES_BK_FILE_TRANSFORMED_LOCATION)
    else:
        return None