'Run a function nested within a group level.
:param function: Callable to run.
:param tag: An optional tag name for the group.  If None (default)
function.__name__ will be used.
:param dargs: Named arguments for the function.'

def run_group(self, function, tag=None, **dargs):

    if tag:
        name = tag
    else:
        name = function.__name__
    try:
        return self._rungroup(subdir=None, testname=name, function=function, timeout=None, **dargs)
    except (SystemExit, error.TestBaseException):
        raise
    except Exception as e:
        raise error.UnhandledTestError(e)
