Word here should be 'functions'

Those two lines are not what I expect - and my Python interpreter agrees. So perhaps that is a typo? I don't know Python well enough to guess the Levenshtein distance to what was intended here.

Aha - it's further down - we just need to stick in this initializer first:

d = {(x, x + 1): x for x in range(10)} # Create a dictionary with tuple keys