Return what kind of Python this is

def get_py_impl():
    """Return what kind of Python this is"""
    if hasattr(sys, 'pypy_version_info'):
        pyimpl = 'PyPy'
    elif sys.platform.startswith('java'):
        pyimpl = 'Jython'
    elif sys.platform == 'cli':
        pyimpl = 'IronPython'
    else:
        pyimpl = 'CPython'
    return pyimpl