def enable_from_env(state=None):
try:<EOL><INDENT>x = os.environ.get(<EOL>ENVVAR,<EOL>state,<EOL>)<EOL>value = bool(int(x))<EOL><DEDENT>except Exception:  <EOL><INDENT>value = bool(state)<EOL><DEDENT>return enable(value)<EOL>
Enable certification for this thread based on the environment variable `CERTIFIABLE_STATE`.

:param bool state:
    Default status to use.
:return:
    The new state.
:rtype:
    bool