public void Number_Method()
    {
      Assert.Throws<ArgumentNullException>(() => new LawsLawApiCall().Number(null));
      Assert.Throws<ArgumentException>(() => new LawsLawApiCall().Number(string.Empty));

      var call = new LawsLawApiCall();
      Assert.False(call.Parameters.ContainsKey("number"));
      Assert.True(ReferenceEquals(call.Number("number"), call));
      Assert.Equal("number", call.Parameters["number"]);
    }