How to shadow built-in class graph?

Dear all,

Suppose I have written a special function called "graph.m" in current directory.

"graph.m" also happens to be a built-in class of MATLAB. Even though the current directory contains the file "graph.m", or the PATH contains current directory, the precedence of the built-in class is always higher than that of my "graph.m".

which -all graph

did show my "graph.m", but MATLAB also indicated that my "graph.m" is shadowed.

How can I promote the precedence of my "graph.m", or how can I shadow the built-in class graph?

Thanks.