With the following small function, digging into a tree-shaped dictionary becomes quite easy:

dig.py

def dig(tree, path):
    for key in path.split("."):
        if isinstance(tree, dict) and tree.get(key):
            tree = tree[key]
        else:
            return None
    return tree
  
  #EXAMPLE
#   mydict = {
#   'Apple': {'American':'16', 'Mexican':10, 'Chinese':5},
#   'Grapes':{'Arabian':'25','Indian':'20'} }

# Now, dig(mydict, "Apple.Mexican") returns 10, while dig(mydict, "Grape") yields the subtree {'Arabian':'25','Indian':'20'}. If a key is not contained in the dictionary, dig returns None.

# Note that you can easily change (or even parameterize) the separator char from '.' to '/', '|' etc.