请为下面给出的类实现一个新的方法"get_full_name()"，该方法应该返回该人员的全名（包括名和姓）。
``` python
class Person:
    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name
```
``` python
class Person:
    def __init__(self, first_name, last_name):
        self.first_name = first_name
        self.last_name = last_name
    
    def get_full_name(self):
        return self.first_name + " " + self.last_name
```