类型错误：参数 1 必须是 pygame.Surface，而不是类型

Question

I'm making a submarine game in python, but when I try to run it, the interpreter gives me very strange error: "TypeError: argument 1 must be pygame.Surface, not type." I tried to search the web for my answer, but it seems like this isn't very usual error. I also tried to find error by myself, but everything seemed fine to me. Here 's part of the code that I think error is in:

mina = pygame.image.load('mina.png')
class mina():
    def __init__(self, x , y):
        self.x = x
        self.y = y
        self.eksplozija = False
    def naris(self):
        screen.blit(mina, (self.x, self.y))
igralec = podmornica(150, 300, 10)
eksploziv = mina(700, 350)
metki = []
clock = pygame.time.Clock()
def grafika():
    clock.tick(60)
    screen.blit(ozadje, (0,0))
    igralec.naris()
    #line, that doesn't work:
    eksploziv.naris()
    for metek in metki:
        metek.naris(screen)
    pygame.display.flip()

Answer 1

The variable mina and the class mina have the same name. The class mina shadows the variable mina . You need to rename one or the other. I recommend to rename the calss mina to Mina , since Python classes use the CapWords convention ( PEP 8 -- Style Guide for Python Code ):

class mina():

class Mina():

eksploziv = mina(700, 350)

eksploziv = Mina(700, 350)