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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fetch(cls, channel, start, end, host=None, port=None, verbose=False, connection=None, verify=False, pad=None, allow_tape=None, scaled=None, type=None, dtype=None):
 """Fetch data from NDS Parameters channel : `str`, `~gwpy.detector.Channel` the data channel for which to query start : `~gwpy.time.LIGOTimeGPS`, `float`, `str` GPS start time of required data, any input parseable by `~gwpy.time.to_gps` is fine end : `~gwpy.time.LIGOTimeGPS`, `float`, `str` GPS end time of required data, any input parseable by `~gwpy.time.to_gps` is fine host : `str`, optional URL of NDS server to use, if blank will try any server (in a relatively sensible order) to get the data port : `int`, optional port number for NDS server query, must be given with `host` verify : `bool`, optional, default: `False` check channels exist in database before asking for data scaled : `bool`, optional apply slope and bias calibration to ADC data, for non-ADC data this option has no effect connection : `nds2.connection`, optional open NDS connection to use verbose : `bool`, optional print verbose output about NDS progress, useful for debugging; if ``verbose`` is specified as a string, this defines the prefix for the progress meter type : `int`, optional NDS2 channel type integer dtype : `type`, `numpy.dtype`, `str`, optional identifier for desired output data type """

        return cls.DictClass.fetch(
            [channel], start, end, host=host, port=port, verbose=verbose,
            connection=connection, verify=verify, pad=pad, scaled=scaled,
            allow_tape=allow_tape, type=type, dtype=dtype)[str(channel)]