'is' operation in terminal and in Pycharm

I am aware of the difference of 'is' operator with strings. However, when I type the following example in Pycharm I get always True.

a = 'a monkey'
b = 'a monkey'
print(a is b)

I get:

True

Where in terminal:

>>> a = 'a monkey'
>>> b = 'a monkey'
>>> a is b
False

Why is this happening?

Edit: Why Pycharm returns always True?