Catch a Specific OSError Exception in Python 3

In Python 3, how can we catch a specific OSError exception?

My current code catches all OSError, but only OSError: [Errno 12] needs to be caught.

try:    foo()except OSError as e:    print('Caught OSError: [Errno12]')

The full error message is:

Caught OSError: [Errno12] Cannot allocate memory

How can we let Python catch only the Errno12 variant of OSError?