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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 _get_column(self, column_or_label):
 """Convert label to column and check column length."""

        c = column_or_label
        if isinstance(c, collections.Hashable) and c in self.labels:
            return self[c]
        elif isinstance(c, numbers.Integral):
            return self[c]
        elif isinstance(c, str):
            raise ValueError('label "{}" not in labels {}'.format(c, self.labels))
        else:
            assert len(c) == self.num_rows, 'column length mismatch'
            return c