錯誤「NoneType」對象有沒有屬性「讀」

Question

我是新來的類和我得到這個錯誤：

self.a2=self.f2.read() 
AttributeError: 'NoneType' object has no attribute 'read' 

這是我的代碼：

class flights(object): 
    """ 
      A class that can read in files about flights and report that information 
    """ 
    def __init__(self, filename1,filename2): 
     """when typing in the filename1 and filename2 make 
     sure to put them is as "filename.txt" 
     """ 
     self.filename1=filename1 
     self.filename2=filename2 
     self.f1=None# none is a place holder 
     self.f2=None 
     self.a1=None 
    def showx(self): 
     print(self.filename1) 
     print(self.filename2) 
    def readfile(self): 
     self.f1=open(self.filename1,'r') 
     self.a1=self.f1.read() 
     self.f1=open(self.filename2,'r') 
     self.a2=self.f2.read() 
     print(self.a1) 
     print(self.a2) 

沒有人知道爲什麼這不起作用？

Answer 1

這條線：

self.f1=open(self.filename2,'r') 

有一個錯字。