def add_state_names(my_df):
    """
    Adds a column of state naems to accompany a corresponding column of state abbreviation.

    Params:
       my_df (pandas.DataFrame) has a column called "abbrev" with state abbreviations

    Returns:
       Copy of the original dataframe, with another column
    """
    new_df = my_df.copy()

    names_map = {"CA": "Cali", "CO": "Colo", "CT": "Conn"}
    # type(my_df['abbrev']) #> class 'pandas.core.series.Series <

    new_df['name'] = my_df['abbrev'].map(names_map)
    return new_df