input: Write a function to count the occurrences of an element x in a list y. Return the count of x in the list.
  def count_x(x, y):
      count = 0
      for i in y:
          if i == x:
              count += 1
      return count
  
  assert count_x(2, [3, 5, 2, 7, 4, 3, 2])==2
  assert count_x(3, [3, 5, 2, 7, 4, 3, 2])==2
  assert count_x(7, [3, 5, 2, 7, 4, 3, 2])==1
  assert count_x(8, [3, 5, 2, 7, 4, 3, 2])==0
  assert count_x(4, [3, 5, 2, 7, 4, 3, 2])==1
output: def count_x(x, y):
      count = 0
      for i in y:
          if i == x:
              count += 1
      return count