def METHOD_NAME(pipenv_instance_pypi):
    """vcrpy has a dependency on `yarl` which comes with a marker
    of 'python version in "3.4, 3.5, 3.6" - this marker duplicates itself:
    'yarl; python version in "3.4, 3.5, 3.6"; python version in "3.4, 3.5, 3.6"'
    This verifies that we clean that successfully.
    """
    with pipenv_instance_pypi() as p:
        c = p.pipenv('install vcrpy==2.0.1')
        assert c.returncode == 0
        assert 'yarl' in p.lockfile['default']
        yarl = p.lockfile['default']['yarl']
        assert 'markers' in yarl
        # Two possible marker sets are ok here
        assert yarl['markers'] in [
            "python_version in '3.4, 3.5, 3.6'",
            "python_version >= '3.4'",
            "python_version >= '3.5'",  # yarl 1.3.0 requires python 3.5.3
        ]