code: def eq(self, event_property, value):
          
          c = self.copy()
          c.filters.append(filters.EQ(event_property, value))
          return c
docs: An equals filter chain.
  
          >>> request_time = EventExpression('request', 'elapsed_ms')
          >>> filtered = request_time.eq('path', '/')
          >>> print(filtered)
          request(elapsed_ms).eq(path, "/")