This is a different repository. The task is asking me to generate a patch for the Django repository's `FileBasedCache.has_key` method. I need to understand the issue and create the appropriate patch based on the problem description.

Based on the issue description, the problem is in `django/core/cache/backends/filebased.py`. The `has_key` method has a race condition:

```python
def has_key(self, key, version=None):
    fname = self._key_to_file(key, version)
    if os.path.exists(fname):
        with open(fname, "rb") as f:
            return not self._is_expired(f)
    return False
```

Between `os.path.exists(fname)` and `open(fname, "rb")`, the file can be deleted by another thread, causing a `FileNotFoundError`.

The fix is to handle the `FileNotFoundError` exception instead of checking if the file exists first. Here's the patch:

--- a/django/core/cache/backends/filebased.py
+++ b/django/core/cache/backends/filebased.py
@@ -91,7 +91,10 @@ class FileBasedCache(BaseCache):
 
     def has_key(self, key, version=None):
         fname = self._key_to_file(key, version)
-        if os.path.exists(fname):
-            with open(fname, "rb") as f:
-                return not self._is_expired(f)
-        return False
+        try:
+            with open(fname, "rb") as f:
+                return not self._is_expired(f)
+        except FileNotFoundError:
+            return False