如何通过实例方法名字的字符串调用方法？

需求：
某项目中，我们的代码使用了三个不同库中的图形类，Circle,Triangle,Rectangle
他们都有一个获取图形面积的接口（方法）但是接口名字不同，我们实现一个统一获取面积的函数，使用每种方法名进行尝试，调用相应类的接口

思路：
1、使用内置函数getattr，通过名称在实例上获取方法对象，然后调用
2、使用标准库下operator下的methodcaller函数调用

代码：

方法一：
lib1.py:

class Circle(object):
    def __init__(self,r):
        self.r = r

    def area(self):
        return self.r ** 2 * 3.14

lib2.py:

class Triangle(object):
    def __init__(self,a,b,c):
        self.a = a
        self.b = b
        self.c = c

    def getArea(self):
        a,b,c = self.a,self.b,self.c
        p = (a+b+c)/2
        area = (p * (p -a) * (p - b )*(p - c)) ** 0.5
        return area

lib3.py:

class Rectangle(object):
    def __init__(self,w,h):
        self.w = w
        self.h = h

    def get_area(self):
        return self.w * self.h

test.py:

from lib1 import Circle
from lib2 import Triangle
from lib3 import Rectangle

# 统一计算面积函数的接口
def getArea(shape):
    for name in ('area','getArea','get_area'):
        f = getattr(shape,name,None) # 这里如果shape不存在属性name，则返回None
        if f:  # 如果存在，则返回计算的结果
            return f()


shape1 = Circle(2)
shape2 = Triangle(3,4,5)
shape3 = Rectangle(6,4)

shapes = [shape1,shape2,shape3]
print map(getArea,shapes)

方法二：
In [15]: from operator import methodcaller

In [16]: methodcaller?
Init signature: methodcaller(self, /, *args, **kwargs)
Docstring:
methodcaller(name, ...) --> methodcaller object

Return a callable object that calls the given method on its operand.
After f = methodcaller('name'), the call f(r) returns r.name().
After g = methodcaller('name', 'date', foo=1), the call g(r) returns
r.name('date', foo=1).
File:           /usr/local/python3/lib/python3.7/operator.py
Type:           type
Subclasses:

In [17]: s = 'abc123abc456'

In [18]: s.find('abc',4)
Out[18]: 6

In [19]: methodcaller('find','abc',4)
Out[19]: operator.methodcaller('find', 'abc', 4)

In [20]: methodcaller('find','abc',4)(s)
Out[20]: 6

====================================================================
>>> s = 'abc123'
>>> s.find('123'
... )
3
>>> # s 'find'
>>> getattr(s,'find')
<built-in method find of str object at 0x7f74c52fa110>
>>> getattr(s,'find')('123')
3
>>> getattr(s,'pop')
Traceback (most recent call last):
  File "<ipython-input-69-bdad44c9326c>", line 1, in <module>
    getattr(s,'pop')
AttributeError: 'str' object has no attribute 'pop'

>>> getattr(s,'pop',None)
in __del__
>>> from operator import methodcaller
>>> s = 'abc123abc456'
>>> s.find('abc',3)
6
>>> methodcaller('find','abc',3)
operator.methodcaller('find', 'abc', 3)
>>> methodcaller('find','abc',3)(s)
6
>>> 
=========================================================================
from lib1 import Circle
from lib2 import Triangle
from lib3 import Rectangle
from operator import methodcaller

def get_area(shape,method_name = ['area','get_area','getArea']):
    for name in method_name:
        if hasattr(shape,name):
            return methodcaller(name)(shape)
        # f = getattr(shape,name,None)
        # if f:
            # return f()
        
shape1 = Circle(1)
shape2 = Triangle(3,4,5)
shape3 = Rectangle(4,6)

shape_list = [shape1, shape2,shape3]
# 获得面积列表
area_list = list(map(get_area,shape_list))
print(area_list)