issue2551350 - Python changes for 3.12 with roundup 2.3.0 cgitb.py Fix change in pydoc.html.header() signature. It dropped foreground and background color arguments in 3.11 and newer. Also enable test code for the html function.

try:
    # Python 3+
    from time import perf_counter
except (ImportError, AttributeError):
    # Python 2.5-2.7
    from time import clock as perf_counter  # noqa: F401