code: def BDEVolumeOpen(bde_volume, path_spec, file_object, key_chain):
    
    password = key_chain.GetCredential(path_spec, 'password')
    if password:
      bde_volume.set_password(password)
  
    recovery_password = key_chain.GetCredential(path_spec, 'recovery_password')
    if recovery_password:
      bde_volume.set_recovery_password(recovery_password)
  
    startup_key = key_chain.GetCredential(path_spec, 'startup_key')
    if startup_key:
      bde_volume.read_startup_key(startup_key)
  
    bde_volume.open_file_object(file_object)
docs: Opens the BDE volume using the path specification.
  
    Args:
      bde_volume (pybde.volume): BDE volume.
      path_spec (PathSpec): path specification.
      file_object (FileIO): file-like object.
      key_chain (KeyChain): key chain.