Be invoked when visiting a node of function call.

        @param node: currently visiting node

def visit_Call(self, nodeCall):
        """
        Be invoked when visiting a node of function call.

        @param node: currently visiting node
        """
        super(PatternFinder, self).generic_visit(nodeCall)
        # Capture assignment like 'f = getattr(...)'.
        if hasattr(nodeCall.func, "func"):
            # In this case, the statement should be
            # 'f = getattr(...)()'.
            nodeCall = nodeCall.func
        # Make sure the function's name is 'getattr'.
        if not hasattr(nodeCall.func, "id"):
            return
        if nodeCall.func.id != "getattr":
            return

        # Capture 'f = getattr(foo, "bar_%s" % baz )' or
        # 'f = getattr(foo, "bar_" + baz )'.
        nodeArgument = nodeCall.args[1]
        if not isinstance(nodeArgument, ast.BinOp):
            return
        operation = nodeArgument.op
        if type(operation) not in [ast.Mod, ast.Add]:
            return
        nodePattern = nodeArgument.left
        if not isinstance(nodePattern, ast.Str):
            return
        pattern = nodePattern.s
        if not ((type(operation) == ast.Add and pattern.endswith("_")) or
                (pattern.count("%s") == 1 and pattern.endswith("_%s"))):
            return
        pattern = pattern.replace("%s", "")
        if pattern[:1].isalpha() and not pattern[:1].islower():
            self.patternsClass.add(pattern)
        else:
            self.patternsFunc.add(pattern)