input: Write a python function to delete an element from a given array.
  assert deleteElem([1, 2, 3, 4, 5], 3)==[1, 2, 4, 5]
  assert deleteElem([10, 20, 30, 40, 50], 20)==[10, 30, 40, 50]
  assert deleteElem([5, 7, 9, 11, 13], 9)==[5, 7, 11, 13]
output: def deleteElem(arr, elem):
      if elem in arr:
          arr.remove(elem)
      return arr