Using Python:

a. Write an accumulator recursive factorial function, with a helper function that is nested within. (Do not use default parameters.) Add type checking so that only int args work.

b. Write a combination function C(n,k). Write a function T(n) that returns a function of one argument k that computes C(n,k).

Example: >>> f = T(10) ; f(3) # f computes C(10,k)

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