loads a ASCII text file grid to self

def load(self, fname):
        """ loads a ASCII text file grid to self  """
        
        # get height and width of grid from file
        self.grid_width = 4
        self.grid_height = 4
        
        # re-read the file and load it
        self.grid = [[0 for dummy_l in range(self.grid_width)] for dummy_l in range(self.grid_height)]
        with open(fname, 'r') as f:
            for row_num, row in enumerate(f):
                if row.strip('\n') == '':
                    break
                for col_num, col in enumerate(row.strip('\n')):   
                    self.set_tile(row_num, col_num, col)