Look up a column by name.

        Parameters
        ----------
        name : str
            Name of the column to look up.

        Returns
        -------
        column : zipline.pipeline.data.BoundColumn
            Column with the given name.

        Raises
        ------
        AttributeError
            If no column with the given name exists.

def get_column(cls, name):
        """Look up a column by name.

        Parameters
        ----------
        name : str
            Name of the column to look up.

        Returns
        -------
        column : zipline.pipeline.data.BoundColumn
            Column with the given name.

        Raises
        ------
        AttributeError
            If no column with the given name exists.
        """
        clsdict = vars(cls)
        try:
            maybe_column = clsdict[name]
            if not isinstance(maybe_column, _BoundColumnDescr):
                raise KeyError(name)
        except KeyError:
            raise AttributeError(
                "{dset} has no column {colname!r}:\n\n"
                "Possible choices are:\n"
                "{choices}".format(
                    dset=cls.qualname,
                    colname=name,
                    choices=bulleted_list(
                        sorted(cls._column_names),
                        max_count=10,
                    ),
                )
            )

        # Resolve column descriptor into a BoundColumn.
        return maybe_column.__get__(None, cls)