### Question:
TransposedFunction implements BinaryFunction<L, R, T> { public static <L, R, T> TransposedFunction<R, L, T> transpose(BinaryFunction<? super L, ? super R, ? extends T> f) { return null == f ? null : new TransposedFunction<R, L, T>(f); } TransposedFunction(BinaryFunction<? super R, ? super L, ? extends T> function); final T evaluate(L left, R right); @Override final boolean equals(Object obj); @Override int hashCode(); @Override String toString(); static TransposedFunction<R, L, T> transpose(BinaryFunction<? super L, ? super R, ? extends T> f);  }### Answer:
@Test public void testTransposeNull() throws Exception { assertNull(TransposedFunction.transpose(null)); }
@Test public void testTranspose() throws Exception { assertNotNull(TransposedFunction.transpose(Constant.of("x"))); }