text: from .printer import Printer
  
  class Expectation:
  
      def __init__(self, browser):
          self.printer = Printer()
          self.b = browser
  
      def expect(self, element_lookup):
          
          for selector, message in element_lookup:
              instruction = "We need an element with selector: {0}" . format(selector)
              element_exists = self.b.is_element_present_by_css(selector)
              self.assertTrue( element_exists, message, instruction )
  
      def expect_not(self, element_lookup):
  
          for selector, message in element_lookup:
              instruction = "Element: {0} - should not be on this page" . format(selector)
              element_not_exists = self.b.is_element_not_present_by_css(selector)
              self.assertTrue( element_not_exists, message, instruction )
  
      def assert_true(self, condition, message):
  
          try:
              assert condition 
              self.printer.record_pass(message)
          except AssertionError:
              self.printer.record_fail(message)
  
  