def _setup_no_fallback(parser):
cli_dest = '<STR_LIT>'<EOL>halp = ('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>')<EOL>tox_pyenv_group = parser.argparser.add_argument_group(<EOL>title='<STR_LIT>'.format(__title__),<EOL>)<EOL>tox_pyenv_group.add_argument(<EOL>'<STR_LIT>', '<STR_LIT>',<EOL>dest=cli_dest,<EOL>default=True,<EOL>action='<STR_LIT>',<EOL>help=halp<EOL>)<EOL>def _pyenv_fallback(testenv_config, value):<EOL><INDENT>cli_says = getattr(testenv_config.config.option, cli_dest)<EOL>return cli_says or value<EOL><DEDENT>parser.add_testenv_attribute(<EOL>name=cli_dest,<EOL>type="<STR_LIT:bool>",<EOL>postprocess=_pyenv_fallback,<EOL>default=False,<EOL>help=('<STR_LIT>'<EOL>'<STR_LIT>'<EOL>'<STR_LIT>'),<EOL>)<EOL>
Add the option, --tox-pyenv-no-fallback.

    If this option is set, do not allow fallback to tox's built-in
    strategy for looking up python executables if the call to `pyenv which`
    by this plugin fails. This will allow the error to raise instead
    of falling back to tox's default behavior.