code: private void checkm() throws DatatypeException, IOException {
          if (context.length() == 0) {
              appendToContext(current);
          }
          current = reader.read();
          appendToContext(current);
          skipSpaces();
  
          checkArg('m', "x coordinate");
          skipCommaSpaces();
          checkArg('m', "y coordinate");
  
          boolean expectNumber = skipCommaSpaces2();
          _checkl('m', expectNumber);
      }
docs: Checks an 'm' command.