def select_geography(ycom_df, geography):
    """
    Helper function for get_ycom_counties
    Takes in Data frame of YCOM 2018 data and filters
    the rows of data within the given geography:
    'National', 'State', 'County', 'cd115', 'CBSA'
    """
    # selecting only the county rows and reseting the index.
    ycom_county = ycom_df.loc[ycom_df['GeoType'] == geography]
    ycom_county = ycom_county.reset_index(drop=True)
    return ycom_county