Square root in python

Square root in python

from math import *

def square_root(number,wie_genau):
    'Heron'
    if number>0:
        x_one=decimal.Decimal(number);y_one=decimal.Decimal(1)
        for i in range(int(wie_genau)):
            x_two=decimal.Decimal(((x_one+y_one)/2))
            y_two=decimal.Decimal((number/x_one))
            #
            x_one=x_two
            y_one=y_two
        return decimal.Decimal(x_one)
    else:
        print("No Negative Numbers!")

Author:Marcin Cherek

Language:Python 3.4

Info: A little Implementation of the math function square root in python. I am using the Heron Algorithm.