input: Write a python function to check if a sequence of operations (push and pop) on the stack results in an empty stack.
  assert sequence_results_in_empty_stack(['push', 'push', 'pop', 'pop']) == True
  assert sequence_results_in_empty_stack(['push', 'pop', 'pop']) == False
  assert sequence_results_in_empty_stack(['push', 'push', 'pop']) == False
output: def sequence_results_in_empty_stack(operations):
      stack = 0
      for op in operations:
          if op == 'push':
              stack += 1
          elif op == 'pop':
              if stack == 0:
                  return False
              stack -= 1
      return stack == 0