Visitor for `FunctionCall` AST node.

def visit_FunctionCall(self, node):
        """Visitor for `FunctionCall` AST node."""
        call = self.memory[node.identifier.name]._node
        args = [self.visit(parameter) for parameter in node.parameters]

        if isinstance(call, AST):
            current_scope = self.memory.stack.current.current
            memory_functions = {
                key: current_scope[key]
                for key in current_scope
                if isinstance(current_scope[key], Function)
            }

            self.memory.append_frame()
            for i, arg in enumerate(args):
                self.memory[i] = arg

            for function in memory_functions:
                self.memory[function] = memory_functions[function]

            function_result = self.visit(call)

            self.memory.pop_frame()
            return function_result
        else:
            return bind_type(call(*args))