Make one object become another.

In [1]: class C:
   ...:     pass
   ...:

In [2]: class D:
   ...:     pass
   ...:

In [3]: c = C()

In [4]: d = D()

In [5]: tup = c, d

In [6]: ls = [c, d]

In [7]: from become import become

In [8]: become(c, d)  # returns the number of places where c existed
Out[8]: 10

In [9]: c
Out[9]: <__main__.D at 0x7f5b04285be0>

In [10]: d
Out[10]: <__main__.D at 0x7f5b04285be0>

In [11]: c is d
Out[11]: True

In [12]: tup
Out[12]: (<__main__.D at 0x7f5b04285be0>, <__main__.D at 0x7f5b04285be0>)

In [13]: ls
Out[13]: [<__main__.D at 0x7f5b04285be0>, <__main__.D at 0x7f5b04285be0>]

In [14]: tup[0] is tup[1] is ls[0] is ls[1] is d is c
Out[14]: True