code: def visit_Call(self, node):
          
          md.visit(self, node)
          for arg in node.args:
              self.visit(arg)
          self.func_args_lazyness(node.func, node.args, node)
          self.visit(node.func)
docs: Compute use of variables in a function call.
  
          Each arg is use once and function name too.
          Information about modified arguments is forwarded to
          func_args_lazyness.