title: The number is added instead of taken away and i dont know why?
body: <p>I'm still messing around In Tkinter but trying to make a balance currently as well as a spent list. This should in theory every time it is triggered decrease the spent value by 10. But it instead increases it by 10</p>
  
  <p>I've already tried moving around where Spent2 is defined but I just get a not defined error. I think it might be because of the fact that it becomes a negative number? So when I take the spent2 value from the Balance value it adds it instead. If so how would I get round the problem</p>
  
  <p>Member class</p>
  
  <pre><code>class Member:
      year = 0
      spent2 = 0
      def __init__(self, name, rank, spent):
          self.name = name
          self.rank = rank
          self.spent = spent
  
      def sal(self):
          rank10 = str(int(self.rank) * 100)
          print(self.name +" is earning "+ rank10)
  
      def bal_year(self):
          bal10 = str(int(self.rank) * 100 * int(self.year) - int(self.spent))
          print(self.name +" has £"+ bal10)
  </code></pre>
  
  <p>Sp10 Called</p>
  
  <pre><code>def bread():
      br=Tk()
  
      def sp(old:Tk):
          old.destroy()
          Tiger()
          sp10()
  
  
  
  
      br.title('Bread')
      l4 = Label(br, text="What would you like to buy Tiger bread, a Bageutte or a Loaf Bread?").pack()
      br1 = Button(br, text = "Buy Tiger Bread", command = lambda: sp(br))
      br1.pack()
  </code></pre>
  
  <p>Changing Spent value</p>
  
  <pre><code>def sp10():
      Member.spent2 = (Member.spent2 - int(10))
  </code></pre>
  
  <p>A test of my Class Member</p>
  
  <pre><code>def balance():
      doppy = Member("DoppyRex", "6", Member.spent2)
      doppy.bal_year()
  </code></pre>
  
  <p>I expect it to decrease the overall balance by 10 but it increases it by 10 instead.</p>