Just some experimentation that I wanted to save. No point to make it private.

uniqueFolderFinder.py

"""
  Looking for a way to reduce a list of 9 digits into a sum that is unique if the digits are those between 1 and 9 inclusively.
  This is for a solution to a Sudoku problem, but it was fun to mess around with functional programming.
"""

import itertools, functools, inspect

def findAllSimilar(individualOperation, aggregationOperation):
  # Note: doing range inverse to make sure operation is commutative
  expected = functools.reduce(aggregationOperation, map(individualOperation, range(9, 0, -1)))

  return map(lambda x: str(x[1]),
          filter(lambda x: x[0] == expected,
            map(lambda x: (
                  functools.reduce(aggregationOperation,
                    map(individualOperation, x)
                  ),
                  x
                ),
                itertools.combinations_with_replacement(range(1,10), 9)
            )
          )
        )

print(
  str.join('\n',
    map(lambda x: str(inspect.getsource(x[1])),
      filter(lambda x: x[0] == 1, 
        map(lambda x: (sum(1 for everything in findAllSimilar(x[0],x[1])), x[0], x[1]),
          [
            ((lambda x: x**5), (lambda x,y: x+y)),
            ((lambda x: x), (lambda x,y: x/y)),
          ]
        )
      )
    )
  )
)