def transform_input_df(df_input):
    """
    Try to clean this up (especially null row test with try/except pass)
    TODO: Alert User that there should only be 4 columns: street, city, state, and zip in the df_input
    """
    if df_input.isnull().values.any():
        print(
            'The input dataframe has null value(s). Dropping the rows with at least one null value and proceeding...'
            )
        df_input = df_input.dropna()
        print('Dropped the rows with any null value.')
    print('Dropping duplicates...')
    df_input = df_input.drop_duplicates()
    df_input['address'] = df_input[['street', 'city', 'state', 'zip']].apply(
        lambda x: ', '.join(x), axis=1)
    return df_input
