code: def in_array(self, event_property, value):
          
          c = self.copy()
          c.filters.append(filters.IN(event_property, value))
          return c
docs: An in-array filter chain.
  
          >>> request_time = EventExpression('request', 'elapsed_ms')
          >>> filtered = request_time.in_array('path', '/event')
          >>> print(filtered)
          request(elapsed_ms).in(path, ["/", "e", "v", "e", "n", "t"])
          >>> filtered = request_time.in_array('path', ['/event', '/'])
          >>> print(filtered)
          request(elapsed_ms).in(path, ["/event", "/"])