Is it possible to place a macro in a namespace in c++?

My application uses another output than the standard output for logging information, which is why I wrote my own Log(), Error(), Panic() and Assert() functions. To organize things nicely, I enclose all the debugging stuff in a Debug namespace.

It would make more sense for the Assert() function to also provide a source file and line number, which is only possible using the __LINE__ and __FILE__ macros. However, it is pretty unpleasant, inefficient etc... to always have to specify these two parameters.

So this is how my code would look like:

namespace Debug {
   void Assert (int condition, std::string message, std::string file, int line);
}

My question is, is it possible to place a macro which includes those two parameters inside the Debug namespace? Like this:

namespace Debug {
   void Assert_ (int condition, std::string message, std::string file, int line);
   #define Assert(a,b) Assert_(a, b, __FILE__, __LINE__)
}

// .... Somewhere where I call the function ....
Debug::Assert (some_condition, "Some_condition should be true");

// Output: Assertion failed on line 10 in file test.cpp:
//           Some_condition should be true

Is this valid c++? If not, is there any way of making this work?