Write the function `resistor_parallel` that receive an undefined number of resistances parallel resistors and return the total resistance.

You can assume that there will be no 0 as parameter.  
Also there will be at least 2 arguments.

Formula:  
`total = 1 / (1/r1 + 1/r2 + .. + 1/rn)`

Examples:  
`resistor_parallel(20, 20)` will return `10.0`  
`resistor_parallel(20, 20, 40)` will return `8.0`

Source: codewars | Difficulty: EASY
Tags: Fundamentals

Starter code: def resistor_parallel(*resistors):
	

Solutions:
def resistor_parallel(*rs):
	return 1 / sum((1.0 / r for r in rs))


def resistor_parallel(*resistances):
	return 1 / sum((1.0 / r for r in resistances))


def resistor_parallel(*xs):
	return 1 / sum((1 / x for x in map(float, xs)))


resistor_parallel = lambda *args: 1 / sum((1.0 / i for i in args))


def resistor_parallel(*resistors):
	return 1 / sum((1 / resistor for resistor in resistors))


def resistor_parallel(*args):
	sum = 0
	for i in args:
		sum += 1 / i
	return 1 / sum


def resistor_parallel(*args):
	return 1 / sum((1.0 / a for a in args))


def resistor_parallel(*resistors):
	return 1.0 / sum(map(lambda x: 1.0 / x, resistors))


resistor_parallel = lambda *args: 1 / sum((1.0 / x for x in args))


from functools import reduce

def resistor_parallel(*res):
	return 1 / reduce(lambda x, y: x + y, [1 / x for x in res])