How do I get a response when I call

response = gemini_pdf(message)
I want response to contain the final output. I’m stuck here.

Here is my code:

def read_pdf(file_path):
    global file_content
    global file_name
 
    
    # Read the contents of the PDF file
    pdfreader = PdfReader(file_path)
    from typing_extensions import Concatenate
    # read text from pdf
    raw_text = ''
    try:
        for i, page in enumerate(pdfreader.pages):
            content = page.extract_text()
            if content:
                raw_text += content

        print(raw_text)
        text_splitter = CharacterTextSplitter(
            separator = "n",
            chunk_size = 800,
            chunk_overlap  = 200,
            length_function = len,
    )
        new_content = text_splitter.split_text(raw_text)
        len(new_content)
        embeddings = GoogleGenerativeAIEmbeddings(model = "models/embedding-001")
        file_content = FAISS.from_texts(new_content, embeddings)
        

    except TypeError as e:
        
        print("Sorry, an error occurred while processing your request.", f"{e}")
        pass
    except FileNotFoundError as e:
        
        print("Sorry, an error occurred while processing your request.", f"{e}")
        pass
    except Exception as e:
        print("Sorry, an error occurred while processing your request.", f"{e}")
        tk.messagebox.showwarning("An error occurred", f"{e}")
        
        return
    
def answer_ftom_pdf(query):
    global file_content
    
    model = ChatGoogleGenerativeAI(model="gemini-1.5-flash-latest",
                            temperature=0.3)

    #prompt = PromptTemplate(template = prompt_template, input_variables = ["context", "question"])
    docs = file_content.similarity_search(query)
    chain = load_qa_chain(model, chain_type="stuff")
    if file_content != None:
        response = chain.run(input_documents=docs, question=query)
        print(response)
        response = response.strip()
        print("Here")
        return response
    if file_content  == None:
        print("Content is none")


def gemini_pdf(query=None):
    global file_content
    global file_name


    if file_content is None:
        # Open a file dialog to select the PDF file
        file_path = filedialog.askopenfilename(filetypes=[("PDF files", "*.pdf")])
        file_name = os.path.basename(file_path)
        if file_name:
            threading.Thread(target=read_pdf, args=(file_path,)).start()

                
    elif file_content:
      
        print("Same PDF")
        threading.Thread(target=answer_ftom_pdf, args=(query,)).start()

How can I ensure response contains the final output when calling gemini_pdf(message)