def _layout_column_width(col):
    """
    Returns the logical column width of a column
    """
    column_equivs = [pi.column_equiv for pi in col.presinfo if pi.column_equiv is not None]
    if len(column_equivs) > 0:
        # assume user has not done something silly like put
        # *2* column_equiv classes on a column
        return column_equivs[0]
    else:
        return 1