python - Syntax error on def -

from tkinter import *  class nodo:      def __init__(self,x,y=none):         self.valor=x         self.sgte=y class cola (nodo):      def __init__(self,n):         self.capa=n         self.prim=none         self.ulti=none     def vacio(self):         if self.prim==none:             return true         return false      def lleno(self):         a=self.prim         b=0         while a!=none:             a=a.sgte             b=b+1         if b==self.capa: return true         else: return false     def existe (self,x):         a=self.prim         while a!= none:             if a.valor== x:                 return true             a=a.sgte         return false      def poner (self,x):         nodo=nodo(x,none)         if x.isalpha()==true or x.isdigit()==true:             if self.lleno() == true:                 raise colallena()             if self.existe()==true:                 raise yaexiste()             if self.vacio() ==true:                 self.prim=nodo                 self.ulti=nodo             if self.vacio()==false:                 self.ulti.sgte=nodo     def sacar (self,x):         if self.empty()==true:             raise colavacia()         a=self.prim.valor         if self.prim.sgte !=none:             self.prim=self.prim.sgte         return      def str(self,x):         if self.vacio()==true:             return ""         else:             a=self.prim             l=[]             while a!=none:                 l.append(a.valor)                 a=a.sgte             l=""             in l:                 i=str(i)                 l=l+" "+i             return l  class colallena (exception):      def __init__(self):         pass class yaexiste (exception):      def __init__(self):         pass class colavacia (exception):      def __init__(self):         pass   c1=cola(10)  c2=cola(20)  def atender1():      if c1.empty()== true:         r1.delete(0,end)         r1.insert(0,"cola vacia")     else:         a=c1.sacar()         r1.config(text=("atendiendo a:"+str(a))  def atender2():      if c2.empty() == true:         r2.delete(0,end)         r2.insert(0,"cola vacia")     else:         a=c2.sacar()         r2.config(text=("atendiendo a:"+str(a)) 

i have syntax error in def atender (x), in def, don't know why, check code , still can't find problem , please :c

the line before missing closing parenthesis:

r1.config(text=("atendiendo a:"+str(a)) #    ----^   --^                ---^ ^^ 

you have 3 opening parenthesis, closing 2. second opening parenthesis can dropped:

r1.config(text="atendiendo a:" + str(a)) 

you have same problem few lines down:

r2.config(text=("atendiendo a:"+str(a)) #    ----^   --^                ---^ ^^