property fail on fget, fset

Please provide more information to help us understand the issue:

• Are you reporting a bug, or opening a feature request?
  Bug
• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

class A():
    @property
    def a(self) -> float:
        return 0.5

class B():
    @property
    def a(self) -> float:
        return 1.5

class C(A, B):
    is_a:bool = True
    @property
    def a(self) -> float:
        if self.is_a:
            return A.a.fget(self)
        else:
            return B.a.fget(self)


if __name__ == '__main__':
    c = C()
    assert c.a ==0.5
    c.is_a = False
    assert c.a == 1.5

• What is the actual behavior/output?

warning: Returning Any from function declared to return "float"
error: "Callable[[A], float]" has no attribute "fget"
warning: Returning Any from function declared to return "float"
error: "Callable[[B], float]" has no attribute "fget"

• What is the behavior/output you expect?
  mypy should pass

• What are the versions of mypy and Python you are using?
  mypy 0.650
Python 3.6.5

  Do you see the same issue after installing mypy from Git master?
  Yes

• What are the mypy flags you are using? (For example --strict-optional)
  no flags.

• If mypy crashed with a traceback, please paste
  the full traceback below.

(You can freely edit this text, please remove all the lines
you believe are unnecessary.)

Beginne damit, mypy auf der minimalen Reproduktion im Issue auszuführen, und vergleiche die Behandlung des Property-Zugriffs über A.a.fget und B.a.fget. Verfolge den Typprüfpfad für Property-Deskriptoren und aufrufbare Attribute; abgeschlossen ist die Aufgabe, wenn das Beispiel mit den erwarteten float-Rückgabetypen erfolgreich durchläuft.