[R] Default Generic function for: args(name, default = TRUE)

[Leonard Mada]

Dear R-Users,

I want to change the args() function to return by default the arguments 
of the default generic function:
args = function(name, default = TRUE) {
     # TODO: && is.function.generic();
     if(default) {
         fn = match.call()[[2]];
         fn = paste0(as.character(fn), ".default");
         name = fn;
     }
     .Internal(args(name));
}

Is there a nice way to find out if a function is generic: something like 
is.function.generic()?

Many thanks,

Leonard
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Note:
- the latest version of this code will be on GitHub:
https://github.com/discoleo/R/commits/master/Stat/Tools.Code.R