from dataclasses import dataclass, field
from typing import List

@dataclass
class Ticket:
    """
    Represents a discrete unit of work within a track.
    """
    id: str
    description: str
    status: str
    assigned_to: str
    depends_on: List[str] = field(default_factory=list)

@dataclass
class Track:
    """
    Represents a collection of tickets that together form an architectural track or epic.
    """
    id: str
    description: str
    tickets: List[Ticket] = field(default_factory=list)