Two permutation iterators for classes in Python with and without a generator

I am just testing out a couple of small classes for learning purposes. Here is my current working code:

class Permutation:
     '''An int list a permutation if starting at any index, one can reach every other index by
     repeated index accesses. The list [4, 0, 3, 1, 2] is a permutation: for example index 0
     stores a 4; index 4 stores a 2; index 2 stores a 3; index 3 stores a 1; index 1 stores a 0,
     bringing us back to that starting position after visiting every index.'''
     def __init__(self, p, start):
         self.p = p
         self.start = start

     def __iter__(self):
         class P_iter:
             def __init__(self, p, start):
                 self.p = p
                 self.start = start
                 self.curr = start
                 self.stahp = False

             def __next__(self):
                 if not self.stahp:
                     current = self.curr
                     self.curr = self.p[self.curr]
                     self.stahp = self.curr == self.start
                     return current
                  else:
                      raise StopIteration
         return P_iter(self.p, self.start)


class Permutation2:
     '''similar to the description above, but its __iter__ method should be implemented by a
     generator (not a P_iter nested class)'''
     def __init__(self,p,start):
         self.p = p
         self.start = start

     def __iter__(self):
         curr = self.start
         stahp = False
         while not stahp:
             yield curr
             curr = self.p[curr]
             stahp = curr == self.start
         else:
             raise StopIteration

I'm looking to clean the code a bit and maybe make it simpler. The code is fully working currently and generates the desired output.