title: Is it faster to create a copy of a nested dictionary or access it directly when passing into a function in Python?
body: <p>I'm passing a dictionary, one element of which is also a dictionary, to a function.
  I want to access the nested dictionary many times within the function,
  and so I was wondering whether it would be faster to create a copy of the nested dictionary as a local variable once at the beginning, and access it directly from that point forward,
  or to access it by way of the outer dictionary every time.</p>