def build_toc_line(toc_line_no_indent: str, no_of_indentation_spaces: int=0
    ) ->str:
    """Build the TOC line.

    :parameter toc_line_no_indent: the TOC line without indentation.
    :parameter no_of_indentation_spaces: the number of indentation spaces.
         Defaults to ``0``.
    :type toc_line_no_indent: str
    :type no_of_indentation_spaces: int
    :returns: toc_line, a single line of the table of contents.
    :rtype: str
    :raises: a built-in exception.
    """
    assert no_of_indentation_spaces >= 0
    indentation = no_of_indentation_spaces * ' '
    toc_line = indentation + toc_line_no_indent
    return toc_line
