TypeError: неподдерживаемые типы операндов для *: '_Printer' и 'float'

Я пытаюсь использовать математику numpy в этом коде, но у меня была ошибка: TypeError: unsupported operand type(s) for *: '_Printer' and 'float'. Может ли кто-нибудь помочь мне с этим? Я не понимаю часть «_Printer». Я новичок в питоне. Благодарю вас!

stumarks = []
class marks_object:
  def __init__(self,CID, SID, m,crd):
    self.CID = CID
    self.SID = SID
    self.m = m
    self.crd = crd

def MarkInput(): 
 CourseID = input("Enter the course's ID : ")
 if CourseID not in [CourseInfo.id for CourseInfo in courselist]:
       print(" The course's id isn't founded! Please try again!")
 else:
  nm = int(input("Number of student that you want to enter marks: "))
  for i in range(nm):
    while True: 
      StuID = input("Enter a student's ID : ")
      if StuID not in [StudentInfo.id for StudentInfo in studentlist]:
        print("The student's ID isn't founded! Please try again! ")
        continue
      break
    marks = RoundDown()
    obj = marks_object(CourseID,StuID,marks,credits)
    stumarks.append(obj)
def avgGPA():
  sid = input("Enter the student's ID : ") 
  coursecredit = []
  coursemark = []
  avgcourse= []
  totalcrd = []
  for course in stumarks:
    if sid in course.SID:
      x = course.crd
      y = course.m
      coursecredit.append(x)
      coursemark.append(y)
      coursecredit = np.array(coursecredit)
      coursemark = np.array(coursemark)
      output = np.multiply(coursecredit,coursemark) # I HAD THE BUG IN THIS LINE