Selenium with Python: Frames 

element = driver.switch_to.active_element

alert = driver.switch_to.alert
driver.switch_to.default_content()
driver.switch_to.frame('frame_name')
driver.switch_to.frame(1)
driver.switch_to.frame(driver.find_elements(By.TAG_NAME, "iframe")[0])
driver.switch_to.parent_frame()
driver.switch_to.window('main')

Example:

#driver.get("https://testlayers.staging.senegalsoftware.com/JobPosts/create?id=326D4402-25C1-4D7E-81DB-23DA5AF14111&step=2")
driver.switch_to.frame(driver.find_element(By.XPATH, '//*[@id="cke_1_contents"]/iframe'))
driver.find_element(By.TAG_NAME, "p").send_keys("Dentist")
driver.switch_to.parent_frame()