How does the in operator work for Python?

In the example below I have two namedtuples that are different objects, but the in operator evaluates to True for an array containing one of the objects.

Is in checking if the array contains the object, or does it check if any object in the array is equivalent? I tried searching for documentation but couldn't find anything specific, just simple examples.

In [3]: a = namedtuple('test', ['t'])                             In [6]: b = a(1)                      In [7]: c = a(1)                      In [8]: b is c                        
Out[8]: False                         In [9]: id(b)                         
Out[9]: 54740808                      In [10]: id(c)                        
Out[10]: 88817352                     In [11]: c in [b]                     
Out[11]: True                         In [12]: b in [c]                     
Out[12]: True                         In [13]: c == b                       
Out[13]: True           

The in operator is checking the array contains the object which value is equivalent. Here is example:

In [1]: a = {}In [2]: b = {}In [3]: c = [a]In [4]: id(a), id(b), id(c[0])
Out[4]: (4514911128, 4515638640, 4514911128)In [5]: a in c
Out[5]: TrueIn [6]: b in c
Out[6]: True