This is the implementation ticket for RFC-205.

The suggested additional text is given below, which probably best fits as a subsection of section 10 of the python style guide:

Code must not be placed inside `if False:` or `if True:` blocks, nor left commented out. If one has debugging code or if one is undecided about which particular implementation to use, such code must be placed inside a "named" `if` statement. Such blocks may have a comment describing the conditions under which said code can be removed (e.g. completion of a ticket, a particular date). For example, for code that will likely be removed in the future, once testing is completed:

# Delete old_thing() and this "if" once we have all the unittests in place (DM-123456).

use_old_method = False

if use_old_method:

    old_thing()

else:

    new_thing()

Such debugging flags should usually be lifted up into the method's keyword arguments to allow users to decide which branch to run. For example:

def foo(x, debug_plots=False):

    do_thing()

    if debug_plots:

        plot_thing()

or, using lsstDebug, which can be controlled as part of a commandline task:

import lsstDebug

def foo(x):

    do_thing()

    if lsstDebug.Info(__name__).debug_plots:

        plot_thing()