### Question:
Hasher { public Hasher putDouble(double d) { hasher.putDouble(d); return this; }  static Hasher of(HashFunction function); HashCode hash(); Hasher put(Hashable hashable); Hasher putAll(Iterable<? extends Hashable> hashables); Hasher putBoolean(boolean b); Hasher putByte(byte b); Hasher putBytes(byte[] bytes); Hasher putChar(char c); Hasher putClass(Class<?> type); Hasher putDouble(double d); Hasher putFloat(float f); Hasher putInt(int i); Hasher putLong(long l); Hasher putShort(short s); Hasher putUnencodedChars(CharSequence charSequence);  }### Answer:
@Test public void testPutDouble() { assertThat(Hasher.of(HASH_FUNCTION).putDouble(0.0).putDouble(1.0).hash()) .isEqualTo(HASH_FUNCTION.newHasher().putDouble(0.0).putDouble(1.0).hash()); }