graph - Tuple index out of range Tkinter -

so i've got program should take function input , graph on tkinter canvas.

    def draw(self):     self.canvas.delete(all)     n, in enumerate(self.sav):         self.function, colour = self.sav_func[n]         = self.p1(i)         = self.p2(i, self.function, colour)         if != [0]:             try:                 self.canvas.create_line(i, fill = colour)             except tclerror err:                 tkmessagebox.showerror(tclerror, err)                 self.sav.remove(self.sav[len(self.sav)-1])                 self.sav_func.remove(self.sav_func[len(self.sav_func)-1]) 

this section giving me following error:

    exception in tkinter callback traceback (most recent call last):   file "c:\python27\lib\lib-tk\tkinter.py", line 1410, in __call__     return self.func(*args)   file "d:/google drive/assign2_2-1.py", line 113, in add_func     self.redraw_all()   file "d:/google drive/assign2_2-1.py", line 132, in redraw_all     self.draw()   file "d:/google drive/assign2_2-1.py", line 145, in draw     self.canvas.create_line(i, fill = colour)   file "c:\python27\lib\lib-tk\tkinter.py", line 2201, in create_line     return self._create('line', args, kw)   file "c:\python27\lib\lib-tk\tkinter.py", line 2182, in _create     cnf = args[-1] indexerror: tuple index out of range 

from can gather it's number of inputs not matching number of outputs, i'm still little lost. great!

it looks i doesn't have enough values. create line needs 4 values: x1,y1,x2,y2.