human
Solve the following python programming problem given the following code:
def aggregate(self, aggregations) : 
    '
    Aggregate data from the tables in this set by performing some
    set of column operations on the groups and coalescing the results into
    a new :class:`.Table`.

    :code:`aggregations` must be a sequence of tuples, where each has two
    parts: a :code:`new_column_name` and a :class:`.Aggregation` instance.

    The resulting table will have the keys from this :class:`TableSet` (and
    any nested TableSets) set as its :code:`row_names`. See
    :meth:`.Table.__init__` for more details.

    :param aggregations:
        A list of tuples in the format :code:`(new_column_name, aggregation)`,
        where each :code:`aggregation` is an instance of :class:`.Aggregation`.
    :returns:
        A new :class:`.Table`.
    ' 
    (column_names, column_types, output, row_name_columns) = _aggregate (self, row_names) 
    if (len (row_name_columns) == 1) : 
        row_names = row_name_columns [0] 
else : 
        def row_names(r) : 
            return tuple ((r [n] for n in row_name_columns)) 
return Table (output, column_names, column_types, row_names = row_names) 

    
    

    Fix the buggy line: (column_names, column_types, output, row_name_columns) = _aggregate (self, row_names)
assistant
#Here is Python program to fix the buggy line: (column_names, column_types, output, row_name_columns) = _aggregate (self, row_names)
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(column_names, column_types, output, row_name_columns) = _aggregate (self, aggregations)