Вот и мы.Панель поиска должна была переключаться нажатием кнопки.
... # Driver initialization, navigating to the page etc.
# The first nested frame
frame_1 = driver.find_element_by_id("widget-container")
driver.switch_to.frame(frame_1)
# The second nested frame
frame_2 = driver.find_element_by_tag_name("iframe")
driver.switch_to.frame(frame_2)
# Toggling the search bar
driver.find_element_by_xpath("//div[contains(text(), 'Instrument')]").click()
# Actually sending in the query
search = driver.find_element_by_xpath("//input[@placeholder='Instrument']")
search.send_keys("Hey there!")