old_contents: #EulerRunner.py
  import datetime
  def solve_problem(solve_func):
      start = datetime.datetime.now()
      result = str(solve_func())
      end = datetime.datetime.now()
      print 'The answer is "' + result + '". Solved in ' + str((end - start).total_seconds()) + 's'
  
  
new_contents: #EulerRunner.py
  import datetime
  def solve_problem(solve_func):
      start = datetime.datetime.now()
      result = str(solve_func())
      end = datetime.datetime.now()
      print 'The answer is "' + result + '". Solved in ' + str((end - start).total_seconds()) + 's'
  
  def fib_generator():
      fib1, fib2 = 0, 1
      yield fib1
      yield fib2
      while True:
          fibtemp = fib1 + fib2
          fib1 = fib2
          fib2 = fibtemp
          yield fib2
  
subject: add fib_generator method