destructor llama error: TypeError: 'NoneType' object is not callable

# Expected Behavior
destructor llama normally

# Current Behavior
# source code:
import bs4
from langchain import hub
from langchain_community.document_loaders import WebBaseLoader
from langchain_chroma import Chroma
from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import RunnablePassthrough
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_community.llms import LlamaCpp
from langchain.embeddings import HuggingFaceBgeEmbeddings

n_gpu_layers = 0
n_batch = 512
_model_path = "/Users/zhouquanquan/software/llama.cpp/models/ggml-meta-llama-3-8b-Q4_K_M.gguf"

llm = LlamaCpp(
model_path=_model_path,
n_gpu_layers=n_gpu_layers,
n_batch=n_batch,
f16_kv=True,
temperature=0,
top_p=1,
n_ctx=8192
)

loader = WebBaseLoader(
web_paths=("https://lilianweng.github.io/posts/2023-06-23-agent/",),
bs_kwargs=dict(
parse_only=bs4.SoupStrainer(
class_=("post-content", "post-title", "post-header")
)
),
)
docs = loader.load()

model_name = "BAAI/bge-small-en-v1.5"
encode_kwargs = {'normalize_embeddings': True} # set True to compute cosine similarity

bge_embeddings = HuggingFaceBgeEmbeddings(
model_name=model_name,
model_kwargs={'device': 'cpu'},
encode_kwargs=encode_kwargs
)

text_splitter = RecursiveCharacterTextSplitter(chunk_size=250, chunk_overlap=0)
splits = text_splitter.split_documents(docs)
vectorstore = Chroma.from_documents(documents=splits, embedding=bge_embeddings)

retriever = vectorstore.as_retriever()
prompt = hub.pull("rlm/rag-prompt-llama3")

def format_docs(docs):
return "\n\n".join(doc.page_content for doc in docs)

rag_chain = (
{"context": retriever | format_docs, "question": RunnablePassthrough()}
| prompt
| llm
| StrOutputParser()
)

print(rag_chain.invoke("What is Task Decomposition in the article?"))
print(rag_chain.invoke("Show me all of the memory types in the article."))

# error:
Exception ignored in:
Traceback (most recent call last):
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/site-packages/llama_cpp/llama.py", line 2091, in __del__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/site-packages/llama_cpp/llama.py", line 2086, in close
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 540, in close
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 532, in __exit__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 517, in __exit__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 322, in __exit__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/site-packages/llama_cpp/_internals.py", line 66, in close
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 540, in close
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 532, in __exit__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 517, in __exit__
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/contextlib.py", line 405, in _exit_wrapper
File "/Users/zhouquanquan/anaconda3/envs/playllm/lib/python3.9/site-packages/llama_cpp/_internals.py", line 60, in free_model
TypeError: 'NoneType' object is not callable

# Environment and Context

1.4 GHz 四核Intel Core i5
Darwin 23.3.0 Darwin Kernel Version 23.3.0: Wed Dec 20 21:28:58 PST 2023; root:xnu-10002.81.5~7/RELEASE_X86_64 x86_64
Python 3.9.18
GNU Make 3.81
Apple clang version 15.0.0 (clang-1500.3.9.4)
llama_cpp_python 0.2.82