mac:driver.find_element_by_name('xxxx').send_keys(Keys.COMMAND,'a')
win:driver.find_element_by_name('xxxx').send_keys(Keys.CONTROL,'a')
mac:driver.find_element_by_name('xxxx').send_keys(Keys.COMMAND,'a')
win:driver.find_element_by_name('xxxx').send_keys(Keys.CONTROL,'a')