I need help with making my claculator

[gareths2017 at cardensv.com]

Im using Python 3.4.2
This is my code:


from tkinter import*

def iCalc(source, side):
    storeObj= Frame(source, borderwidth= 1, bd= 4, bg="powder blue")
    storeObj.pack(side=side, expand=YES, fill=BOTH)
    return storeObj

def button (source, side, text, command=None):
    storeObj= Button(source, text=text, command=command)
    storeObj.pack(side=side, expand=YES, fill=BOTH)
    return storeObj

class app(Frame):
    def __init__(self):
        Frame.__init__(self)
        self.option_add('*Front', 'arial 20 bold')
        self.pack(expand=YES, fill=BOTH)
        self.master.title('Calculator')

        display= StringVar()
        Entry(self, relief=RIDGE,
              textvariable=display, justify='right', bd=30, bg="powder blue").pack(side=TOP, expand=YES,
                                                                                   fill=BOTH)
        for clearBut in(["CE"], ["C"]):
            erase = iCalc(self, TOP)
            for ichar in clearBut:
                button(erase, LEFT, ichar,
                       lambda storeObj=display, q=ichar: storeObj.set(''))

        for NumBut in ("789/", "456*", "123-", "0.+"):
            FunctionNum = iCalc(self, TOP)
            for iEquals in NumBut:
                button(FunctionNum, LEFT, iEquals,
                       lambda storeObj=display, q=iEquals: storeObj.set(storeObj.get() + q))

        EqualsButton=iCalc(self, TOP)
        for iEquals in "=":
            if iEquals == '=':
                btniEquals= button(EqualsButton, LEFT, iEquals)
                btniEquals.bind('<ButtonRelease-1>',
                                lambda e, s=self, storeObj=display: s.calc(storeObj), '+')
            else:
                btniEquals= buton(EqualsButton, LEFT, iEquals,
                                  lambda storeObj=display, s=' %s '%Equals: storeObj.set(storeObj.get()+s))
                                
     

def calc(self, display):
    try:
        display.set(eval(display.get()))
    except:
        display.set("Type an actual equation please!") 



if __name__ == '__main__':
    app().mainloop()