Can't Get Entry Var in Tkinter

[Larz60+]

textvariable must be a tkinter.StringVar, not a raw string.

you can remedy this by declaring a string var in button_label, seting it from the argument variavel
and using the new StringVar as the textvariable (cod not tested):

class Classe1():
    def __init__(self):
        self.svar = StringVar()

    def button_label(self, chosen_row, textoescrito, variavel):
        self.svar.set(variavel)
        lb1 = Label(frame2, text=textoescrito, bg=color2, font=('Roboto', 11))
        lb1.grid(row=chosen_row, column=2, padx=2, pady=2)
        self = Entry(frame2, width=50, font=('Roboto', 11), textvariable=self.svar)
        self.grid(row=chosen_row + 1, column=2, padx=2, pady=2)