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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 _check_spawnable(source_channels, target_channels):
 """Check whether gate is spawnable on the target channels."""

    if len(target_channels) != len(set(target_channels)):
        raise Exception('Spawn channels must be unique')
    return source_channels.issubset(
        set(target_channels))