def METHOD_NAME():
    """Test grammar copying."""
    bs = StringParser("bar", KeywordSegment)
    fs = StringParser("foo", KeywordSegment)
    g1 = OneOf(fs, bs)
    # Check copy
    g2 = g1.copy()
    assert g1 == g2
    assert g1 is not g2
    # Check copy insert (start)
    g3 = g1.copy(insert=[bs], at=0)
    assert g3 == OneOf(bs, fs, bs)
    # Check copy insert (mid)
    g4 = g1.copy(insert=[bs], at=1)
    assert g4 == OneOf(fs, bs, bs)
    # Check copy insert (end)
    g5 = g1.copy(insert=[bs], at=-1)
    assert g5 == OneOf(fs, bs, bs)