nodes: 0, module; 1, function_definition; 2, function_name:iter; 3, parameters; 4, block; 5, identifier:self; 6, identifier:columnnames; 7, default_parameter; 8, default_parameter; 9, expression_statement; 10, import_from_statement; 11, return_statement; 12, identifier:order; 13, string; 14, identifier:sort; 15, True; 16, comment:"""Return a tableiter object.
  
          :class:`tableiter` lets one iterate over a table by returning in each
          iteration step a reference table containing equal values for the given
          columns.
          By default a sort is done on the given columns to get the correct
          iteration order.
  
          `order`
            | 'ascending'  is iterate in ascending order (is the default).
            | 'descending' is iterate in descending order.
          `sort=False`
            do not sort (because table is already in correct order).
  
          For example, iterate by time through a measurementset table::
  
            t = table('3c343.MS')
            for ts in t.iter('TIME'):
              print ts.nrows()
  
          """; 17, relative_import; 18, dotted_name; 19, call; 20, import_prefix; 21, dotted_name; 22, identifier:tableiter; 23, identifier:tableiter; 24, argument_list; 25, identifier:tableiter; 26, identifier:self; 27, identifier:columnnames; 28, identifier:order; 29, identifier:sort
code: def iter(self, columnnames, order='', sort=True):
          """Return a tableiter object.
  
          :class:`tableiter` lets one iterate over a table by returning in each
          iteration step a reference table containing equal values for the given
          columns.
          By default a sort is done on the given columns to get the correct
          iteration order.
  
          `order`
            | 'ascending'  is iterate in ascending order (is the default).
            | 'descending' is iterate in descending order.
          `sort=False`
            do not sort (because table is already in correct order).
  
          For example, iterate by time through a measurementset table::
  
            t = table('3c343.MS')
            for ts in t.iter('TIME'):
              print ts.nrows()
  
          """
          from .tableiter import tableiter
          return tableiter(self, columnnames, order, sort)