In this kata you need to write a function that will receive two strings (```n1``` and ```n2```), each representing an integer as a binary number. A third parameter will be provided (```o```) as a string representing one of the following operators: add, subtract, multiply.

Your task is to write the calculate function so that it will perform the arithmetic and the result returned should be a string representing the binary result.

Examples:
```
1 + 1 === 10
10 + 10 === 100
```

Negative binary numbers are usually preceded by several 1's. For this kata, negative numbers can be represented with the negative symbol at the beginning of the string.

Examples of negatives:
```
1 - 10 === -1
10 - 100 === -10
```

Difficulty: EASY
Starter code: def calculate(n1, n2, o):
	

Solutions:
def calculate(n1, n2, o):
	operators = {'add': lambda x, y: x + y, 'subtract': lambda x, y: x - y, 'multiply': lambda x, y: x * y}
	return '{:b}'.format(operators[o](int(n1, 2), int(n2, 2)))


def calculate(n1, n2, o):

	def s2b(i):
		return int(i, base=2)
	if o == 'add':
		res = s2b(n1) + s2b(n2)
	elif o == 'subtract':
		res = s2b(n1) - s2b(n2)
	elif o == 'multiply':
		res = s2b(n1) * s2b(n2)
	return '{0:b}'.format(res)


def calculate(n1, n2, o):
	ops = {'add': lambda a, b: a + b, 'subtract': lambda a, b: a - b, 'multiply': lambda a, b: a * b}
	n = ops[o](int(n1, 2), int(n2, 2))
	s = str(bin(n))
	return '-' + s[3:] if n < 0 else s[2:]


from operator import add, sub as subtract, mul as multiply

def calculate(n1, n2, o):
	value = globals()[o](int(n1, 2), int(n2, 2))
	return format(value, 'b')


from operator import *

def calculate(n1, n2, o):
	result = eval(o[:3])(int(n1, 2), int(n2, 2))
	return (bin(result)[2:], bin(result)[0] + bin(result)[3:])[result < 0]


import operator

def calculate(n1, n2, o):
	calc = {'add': operator.add(int(n1, base=2), int(n2, base=2)), 'subtract': operator.sub(int(n1, base=2), int(n2, base=2)), 'multiply': operator.mul(int(n1, base=2), int(n2, base=2))}
	return '{:b}'.format(calc[o])


def calculate(n1, n2, o):
	if o == 'add':
		return bin(int(n1, 2) + int(n2, 2))[2:]
	if o == 'subtract':
		result = bin(int(n1, 2) - int(n2, 2))
		if result[0] == '-':
			return result[0] + result[3:]
		return result[2:]
	if o == 'multiply':
		return bin(int(n1, 2) * int(n2, 2))[2:]
	if o == 'divide':
		return bin(int(n1, 2) / int(n2, 2))[2:]


def calculate(n1, n2, o):
	return bin(int(n1, 2) + int(n2, 2) if o == 'add' else int(n1, 2) - int(n2, 2) if o == 'subtract' else int(n1, 2) * int(n2, 2)).replace('0b', '')