Configures the application as "signed in" (displays user's
        name and disables the entry to input phone/bot token/code).

def set_signed_in(self, me):
        """
        Configures the application as "signed in" (displays user's
        name and disables the entry to input phone/bot token/code).
        """
        self.me = me
        self.sign_in_label.configure(text='Signed in')
        self.sign_in_entry.configure(state=tkinter.NORMAL)
        self.sign_in_entry.delete(0, tkinter.END)
        self.sign_in_entry.insert(tkinter.INSERT, utils.get_display_name(me))
        self.sign_in_entry.configure(state=tkinter.DISABLED)
        self.sign_in_button.configure(text='Log out')
        self.chat.focus()