input: Write a function to find the first occurrence of a given element in a list.
  assert find_first_occurrence([1, 2, 3, 4, 5], 3) == 2
  assert find_first_occurrence([10, 20, 30, 40, 50], 40) == 3
  assert find_first_occurrence([5, 7, 9, 7, 5], 7) == 1
output: def find_first_occurrence(lst, element):
      for index, value in enumerate(lst):
          if value == element:
              return index
      return -1