This is a self-contained task. There are no inputs/ to read (not referenced as existing), and the task is a standard LRU cache. I'll write the solution.

The final message must be only the raw content of `solution.py`.

```python
"""LRU (least-recently-used) cache with O(1) average get and put.

Backed by ``collections.OrderedDict``, which keeps insertion order and lets us
move a key to the most-recently-used end and pop the least-recently-used end in
O(1) average time.
"""

from collections import OrderedDict


class LRUCache:
    def __init__(self, capacity):
        if capacity < 0:
            raise ValueError("capacity must be a non-negative integer")
        self._capacity = capacity
        self._store = OrderedDict()

    def get(self, key):
        if key not in self._store:
            return -1
        self._store.move_to_end(key)
        return self._store[key]

    def put(self, key, value):
        if self._capacity == 0:
            return
        if key in self._store:
            self._store[key] = value
            self._store.move_to_end(key)
            return
        self._store[key] = value
        if len(self._store) > self._capacity:
            self._store.popitem(last=False)
```