'Apply a marker to a single test function invocation.
This method is useful if you don\'t want to have a keyword/marker
on all function invocations.
:arg marker: a :py:class:`_pytest.mark.MarkDecorator` object
created by a call to ``pytest.mark.NAME(...)``.'

def applymarker(self, marker):

    try:
        self.node.keywords[marker.markname] = marker
    except AttributeError:
        raise ValueError(marker)
