https://www.codewars.com/kata/function-composition/train/python

Task

Function composition is a mathematical operation that mainly presents itself in lambda calculus and computability. It is explained well here, but this is my explanation, in simple mathematical notation:

f3 = compose( f1 f2 )
   Is equivalent to...
f3(a) = f1( f2( a ) )

Your task is to create a compose function to carry out this task, which will be passed two functions or lambdas. Ruby functions will be passed, and should return, either a proc or a lambda. Remember that the resulting composed function may be passed multiple arguments!

compose(f , g)(x)
=> f( g( x ) )

This kata is not available in haskell; that would be too easy!

Best Practices

Py First:

def compose(f,g):
  return lambda *x: f(g(*x))

Py Second:

def compose(f,g):
    # Compose the two functions here!
    def z(*arg,**kw):
      return f(g(*arg,**kw))
    return z