codewars homework challenges

homework.py

#Multiply
def multiply(a, b):
  return a * b

#Convert num to string
def number_to_string(num):
  return str(num)
  
#Reverse string
def solution(str):
  return str[::-1]

#Return negative
def make_negative( number ):
  if number > 0:
    return -number
  else:
    return number