@classmethod<EOL><INDENT>@io_nds2.open_connection<EOL>def query_nds2_availability(cls, channels, start, end, ctype=<NUM_LIT>,<EOL>connection=None, host=None, port=None):<DEDENT>
start = int(to_gps(start))<EOL>end = int(ceil(to_gps(end)))<EOL>chans = io_nds2.find_channels(channels, connection=connection,<EOL>unique=True, epoch=(start, end),<EOL>type=ctype)<EOL>availability = io_nds2.get_availability(chans, start, end,<EOL>connection=connection)<EOL>return type(availability)(zip(channels, availability.values()))<EOL>
Query for when data are available for these channels in NDS2

        Parameters
        ----------
        channels : `list`
            list of `Channel` or `str` for which to search

        start : `int`
            GPS start time of search, or any acceptable input to
            :meth:`~gwpy.time.to_gps`

        end : `int`
            GPS end time of search, or any acceptable input to
            :meth:`~gwpy.time.to_gps`

        connection : `nds2.connection`, optional
            open connection to an NDS(2) server, if not given, one will be
            created based on ``host`` and ``port`` keywords

        host : `str`, optional
            name of NDS server host

        port : `int`, optional
            port number for NDS connection

        Returns
        -------
        segdict : `~gwpy.segments.SegmentListDict`
            dict of ``(name, SegmentList)`` pairs