code: def element_width_should_be(self, locator, expected):
  		
  
  		self._info("Verifying element '%s' width is '%s'" % (locator, expected))
  		self._check_element_size(locator, 'width', expected)
docs: Verifies the element identified by `locator` has the expected
  		width. Expected width should be in pixels.
  
  		| *Argument* | *Description* | *Example* |
  		| locator | Selenium 2 element locator | id=my_id |
  		| expected | expected width | 800 |