import stringprep


def c12_mapping(char):
    """Do mapping of RFC 3454 C.1.2 space characters to ' '.

    :Parameters:
        - `char`: Unicode character to map.

    :returns: u" " if there is `char` code in the table, `None` otherwise.
    """
    if stringprep.in_table_c12(char):
        return u" "
    else:
        return None