<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _zoom_rows(self, zoom):
 """Zooms grid rows"""


        self.grid.SetDefaultRowSize(self.grid.std_row_size * zoom,
                                    resizeExistingRows=True)
        self.grid.SetRowLabelSize(self.grid.row_label_size * zoom)

        for row, tab in self.code_array.row_heights:
            if tab == self.grid.current_table and \
               row < self.grid.code_array.shape[0]:
                base_row_width = self.code_array.row_heights[(row, tab)]
                if base_row_width is None:
                    base_row_width = self.grid.GetDefaultRowSize()
                zoomed_row_size = base_row_width * zoom
                self.grid.SetRowSize(row, zoomed_row_size)