def str_remove(df, column_name: str, pattern: str = ''):
    """Remove string patten from a column

    Wrapper around df.str.replace()

    Parameters
    -----------
    df: pd.Dataframe
        Input dataframe to be modified
    column_name: str
        Name of the column to be operated on
    pattern: str, default to ''
        String pattern to be removed

    Returns
    --------
    df: pd.Dataframe

    """
    df[column_name] = df[column_name].str.replace(pattern, '')
    return df