Python Compute distance between two points

Compute distance between two points

#a function that computes the distance between two points,
# But does it in a naughty way.

import math

def distance(a,b):
    a[0]=a[0]-b[0]
    a[1]=a[1]-b[1]
    return math.sqrt(a[0]**2+a[1]**2)