#NEWLINE# def _calc_nrows( self , len_data , target_pop ) : #NEWLINE# #INDENT# '\n        Calculate the number of rows to add to or remove from some data.\n\n        Parameters\n        ----------\n        len_data : int\n            The current number of rows in the data table.\n        target_pop : int\n            Target population.\n\n        ' #NEWLINE# return ( target_pop - len_data )