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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_metadata_link(self, ds):
        '''
        Checks if metadata link is formed in a rational manner

        :param netCDF4.Dataset ds: An open netCDF dataset
        '''
        if not hasattr(ds, u'metadata_link'):
            return
        msgs = []
        meta_link = getattr(ds, 'metadata_link')
        if 'http' not in meta_link:
            msgs.append('Metadata URL should include http:// or https://')
        valid_link = (len(msgs) == 0)
        return Result(BaseCheck.LOW, valid_link, 'metadata_link_valid', msgs)