`tabulate` but worse

fmt-table.py

def fmt_table(table, disable_column_headers=False) -> str:
    """
    I would use tabulate but I don't want nonstandard imports
    """
    table_output = ""
    # no row has more elements than the header row
    assert(all(len(row) <= len(table[0]) for row in table))
    column_widths = [ 0 ] * len(table[0])
    for row in table:
        for i,element in enumerate(row):
            if len(str(element)) > column_widths[i]:
                column_widths[i] = len(str(element))
    column_widths = [ x + 3 for x in column_widths ] # room for whitespace on either side
    if not disable_column_headers:
        table_output += "\033[4m" # start underline
        for i,column_header in enumerate(table[0]):
            if i > 0:
                table_output += '|'
            table_output += str(column_header).center(column_widths[i]-1) # minus one for the '|'
        table_output += "\033[0m" # end underline
        table_output += '\n'
        table.pop(0)
    for row in table:
        for i,value in enumerate(row):
            table_output += str(value).ljust(column_widths[i])
        table_output += '\n'
    return(table_output)