def METHOD_NAME(self):
    class SomethingToInterpolate:
        def interpolate_me():
            """First line
            Some description of things, also this:
            Other things are happening now.
            """
        def dont_interpolate_me():
            """First line
            Some description of things, also this:
            Other things are happening now.
            """
    class Subclass(SomethingToInterpolate):
        pass
    @self.registry("a")
    def a():
        """x"""
    @self.registry("b")
    def b():
        """y"""
    @self.registry("c")
    def c():
        """z"""
    subclass_registry = self.registry.copy()
    @subclass_registry("o")
    def o():
        """p"""
    self.registry.interpolate(SomethingToInterpolate, "interpolate_me")
    subclass_registry.interpolate(Subclass, "interpolate_me")
    self.assertEqual(SomethingToInterpolate.interpolate_me.__doc__,
                     "First line\n\n                Some description of th"
                     "ings, also this:\n\n\t'a'\n\t  x\n\t'b'\n\t  y\n\t'c"
                     "'\n\t  z\n\n                Other things are happeni"
                     "ng now.\n                ")
    self.assertEqual(SomethingToInterpolate.dont_interpolate_me.__doc__,
                     "First line\n\n                Some description of th"
                     "ings, also this:\n\n                Other things are"
                     " happening now.\n                ")
    self.assertEqual(Subclass.interpolate_me.__doc__,
                     "First line\n\n                Some description of th"
                     "ings, also this:\n\n\t'a'\n\t  x\n\t'b'\n\t  y\n\t'c"
                     "'\n\t  z\n\t'o'\n\t  p\n\n                Other thin"
                     "gs are happening now.\n                ")
    self.assertEqual(Subclass.dont_interpolate_me.__doc__,
                     "First line\n\n                Some description of th"
                     "ings, also this:\n\n                Other things are"
                     " happening now.\n                ")