Return the columns of this table
        :param int top: specify n columns to retrieve
        :param int skip: specify n columns to skip

def get_columns(self, *, top=None, skip=None):
        """
        Return the columns of this table
        :param int top: specify n columns to retrieve
        :param int skip: specify n columns to skip
        """
        url = self.build_url(self._endpoints.get('get_columns'))

        params = {}
        if top is not None:
            params['$top'] = top
        if skip is not None:
            params['$skip'] = skip
        params = None if not params else params
        response = self.session.get(url, params=params)

        if not response:
            return iter(())

        data = response.json()

        return (self.column_constructor(parent=self, **{self._cloud_data_key: column})
                for column in data.get('value', []))