def METHOD_NAME(self, running_lines, last_row=False):
    """
    Helper for :meth:`_check_tall_list_and_format`
    This helper function processes and outputs the contents of the
    running_lines array.
    TESTS::
        sage: from sage.repl.display.util import format_list
        sage: format_list._tall_list_row(['a   b', 'b  c', 'c'])
        ['a           b', 'b        c', 'c,', '']
    """
    s = []
    for i, line in enumerate(running_lines):
        if i + 1 != len(running_lines):
            sep, tail = '  ', ''
        else:
            # The commas go on the bottom line of this row.
            sep, tail = ', ', '' if last_row else ','
        s.append(sep.join(line) + tail)
    # Separate rows with a newline to make them stand out.
    if not last_row:
        s.append("")
    return s