python - Python3, using object instance within another class -

i'm trying modify class attribute reference object in __init__ method , use in method. sadly following code sample doesn't work expected...

code

class translator:     #list of attributes     parser=none     def __init__(self):             parser = parser_class() ...          #some other commands     def translate(self):           something=self.parser.generatehead() ...          #more commands 

compile err

attributeerror: 'nonetype' object has no attribute 'generatehead' 

i know can give translate method argument, i'm curious why statement within python doesn't work.

you're doing instance attributes wrong.

first off, don't need declare attributes ahead of time. putting parser = none @ top level of class creates class variable named parser, don't think want. in python can add new instance attributes @ time simple assignment: instance.attr = "whatever".

second, when want instance assignment within method, need use self refer instance. if leave off self, you'll assigning local variable inside function, not instance or class variable. actually, specific name self isn't necessary, need use first argument method (and it's not idea break convention of naming self).

so, fix code, this:

class translator:     # don't declare variables @ class level (unless want class variables)      def __init__(self):             self.parser = parser_class()   # use self assign instance attribute      def translate(self):           = self.parser.generatehead()  # should work