class_docstr: File lock based on UNIX-only fcntl module.
      
class_docstr_tok: ["File","lock","based","on","UNIX-only","fcntl","module","."]
code: def release(self):
      if self.fd is None:
          raise Exception("Lock was not acquired")
  
      import fcntl  # @UnresolvedImport
  
      fcntl.flock(self.fd, fcntl.LOCK_UN)
      os.close(self.fd)
      self.fd = None
  
file_path: whoosh/src/whoosh/util/filelock.py
imports: import errno
  import os
  import sys
  import time
label_desc: Use image node_id 2 for calling the FcntlLock obj's underlying member method code with example usage: obj.release() without return types