input: Write a function to simulate a random walk of a given number of steps and return the final coordinates.
  assert random_walk(1) != (0, 0)
  assert isinstance(random_walk(10), tuple)
  assert len(random_walk(10)) == 2
output: import random
  
  def random_walk(steps):
      x, y = 0, 0
      for _ in range(steps):
          direction = random.choice(['N', 'S', 'E', 'W'])
          if direction == 'N':
              y += 1
          elif direction == 'S':
              y -= 1
          elif direction == 'E':
              x += 1
          elif direction == 'W':
              x -= 1
      return (x, y)