from selenium import webdriver

driver = webdriver.Firefox()

class LogIn():

    #do indentyfikowania obiektów
    page = 'adres_strony'
    login_id = 'username'
    password_id = 'password'
    submit_name = 'login-submit'

    #metody:
    def __init__(self):
        driver.get(page)

    def fill_login_field(self, login):
        driver.find_element_by_id(self.login_id).send_keys(login)

    def fill_password_field(self, password):
        driver.find_element_by_id(self.password_id).send_keys(password)

    def submit_login(self):
        driver.find_element_by_name(self.submit_name).click()