Give an error when function with no argument is called with parentheses (or function with argument is called with no parentheses) in \tikzmath?

[user202729]

Brief outline of the proposed feature

\begin{tikzpicture}
	\node{
			\tikzmath{
				function g{
					return 2;
				};
				real \i;
				\i=g;
				print{\i};
			}
			\tikzmath{
				function f(\x){
					return \x;
				};
				real \i;
				\i=f;
				print{\i};
			}
		};
\end{tikzpicture}

Usage example

No response