input: Write a function to remove all occurrences of the given element in a given array.
  
  assert remove_element([2, 4, 5, 7, 4, 2], 4) == [2, 5, 7, 2]
  assert remove_element([1, 1, 1], 1) == []
  assert remove_element([], 3) == []
  assert remove_element([3, 3, 4], 3) == [4]
  assert remove_element([1, 2, 3, 4, 2, 2], 2) == [1, 3, 4]
output: def remove_element(arr, elem):
      return [x for x in arr if x != elem]