class NoSuchStudentException(Exception):
    """Žiak nie je v zozname."""
    
DEFAULT_STUDENTS = [
    "Alena", "Boris", "Cyril", "Daniel", "Eva", "František",
    "Gitka", "Helena", "Ivana", "Jozef", "Karol", "Ladislav",
]

class Garden():
    def __init__(self, diagram: str):
        self.diagram: str = diagram
        self.rows: str = diagram.splitlines()

    def add_rows(self,row):
        if isinstance(row,str):
            raise ValueError("Row has to be string")
        self.rows.append(row)

garden = Garden("VVCG\nVVRC")
print([item[1:3] for item in garden.rows])
garden.rows.append(Garden("s\ns"))
print(garden.rows)