def split_y_and_url(df_column):
    """
    Helper to preprocess_enviro_df. Splits a column in form <"Y"><url>

    Inputs:
        - df_column: df series, representing a column like "Y <url>"

    Outputs:
        - split_df: Pandas dataframe, with columns
        <bool of complaint or enforcement>,
        <url string of complaint or enforcement>
    """
    # Split "Y" from the URL and convert "Y" to True's
    split_df = df_column.str.extract(r'(^Y) \((.*)\)', expand=True)
    split_df.replace('Y', True, inplace=True)  # make boolean

    # Rename columns:
    if df_column.name == 'COMPLAINTS':
        split_df.columns = ["complaints", "complaints_url"]
    else:
        split_df.columns = ["enviro_enforcement", "enviro_enforcement_url"]

    return split_df