code: def find_times(self, site, frametype, gpsstart=None, gpsend=None):
          
          if gpsstart and gpsend:
              url = ("%s/gwf/%s/%s/segments/%s,%s.json"
                     % (_url_prefix, site, frametype, gpsstart, gpsend))
          else:
              url = ("%s/gwf/%s/%s/segments.json"
                     % (_url_prefix, site, frametype))
  
          response = self._requestresponse("GET", url)
          segmentlist = decode(response.read())
          return segments.segmentlist(map(segments.segment, segmentlist))
docs: Query the LDR for times for which frames are avaliable
  
          Use gpsstart and gpsend to restrict the returned times to
          this semiopen interval.
  
          @returns: L{segmentlist<pycbc_glue.segments.segmentlist>}
  
          @param site:
              single-character name of site to match
          @param frametype:
              name of frametype to match
          @param gpsstart:
              integer GPS start time of query
          @param gpsend:
              integer GPS end time of query
  
          @type       site: L{str}
          @type  frametype: L{str}
          @type   gpsstart: L{int}
          @type     gpsend: L{int}