priority_queue.py

import enum
from typing import Any, Optional


class Priority(enum.Enum):
    HIGH = 1
    MEDIUM = 2
    LOW = 3



class PQueue:
    def __init__(self):
        self._x = []

    def is_empty(self):
        return len(self._x) == 0

    def size(self):
        return len(self._x)

    def put(self, obj: Any, priority: Optional[Priority] = Priority.LOW) -> None:
        self._x.append((priority.value, obj))
        # sort in place according to priority: 1= high, 3=low
        self._x.sort(key=lambda x: x[0])

    def get(self) -> Any:
        # we take the first (highest priority)
        if not self.is_empty():
            return self._x.pop(0)[1]
        return None

    def peek(self) -> Any:
        # get without removing from queue
        if not self.is_empty():
            return self._x[0][1]
        return None



pq = PQueue()

pq.put(10)
pq.put(2, Priority.HIGH)
pq.put(3, Priority.MEDIUM)
pq.put(5, Priority.LOW)


print(pq.get())
print(pq.get())
print(pq.get())
print(pq.get())
print(pq.get())