Issue:
I want to send_keys(Keys.LEFT_CONTROL + \'t\')
Now to do this I locate any element on the page
elem = self.browser.find_element_b
You are using WebDriver to interact with the actual elements on the page. It will not work.
Try using the Actions
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.keys import Keys
actions = ActionChains(driver)
actions.send_keys(Keys.LEFT_CONTROL + 't')
actions.perform()
See the documentation: http://selenium-python.readthedocs.io/api.html?highlight=send_keys#module-selenium.webdriver.common.action_chains