Example of pylint seing something not promised as a list

pylint_type.py

import json

class A:

    def __init__(self):
        self.b = None

    @property
    def a(self):
        if self.b is None:
            self.b = json.loads('[]')
        return self.b

    @a.setter
    def a(self):
        print('SETTER')


def main():
    a = A()
    print(a.a)
    a.a.append('hi')
    print(a.a)


main()

E: 22, 4: Method 'a' has no 'append' member (no-member)

To ensure that it's always a list:

    @property
    def a(self):
        if self.b is None:
            self.b = json.loads('[]')
        if not isinstance(self.b, list):
            self.b = list(self.b)
        return self.b

    @property
    def access_modes(self):
        ''' access_modes property '''
        if self._access_modes == None:
            self._access_modes = self.get_access_modes()
        if not isinstance(self._access_modes, list):
            self._access_modes = list(self._access_modes)
        return self._access_modes

    @access_modes.setter
    def access_modes(self, data):
        ''' access_modes property setter'''
        if not isinstance(data, list):
            data = list(data)
        self._access_modes = data

   @property
    def access_modes(self):`
        ''' access_modes property '''
        if self._access_modes is None:
            self._access_modes = self.get_access_modes()
            if not isinstance(self._access_modes, list):
                self._access_modes = list(self._access_modes)

        return self._access_modes