无法调用单独文件结构中的Python函数

Question

我试图更好地组织我的 Python（Python 版本 3.9.2）项目并创建了以下文件结构（我在 Macbook Air M2 上使用 VS Code）。当我尝试调用“函数文件结构”中的函数时，出现以下错误消息：

NameError：名称“getAssetHoldings”未定义

# File structure:
# main.py
my_functions
 _init_.py
 stock_functions.py
 utility_functions.py

# Content of files:
#main.py:
import my_functions
import pandas as pd
import seaborn as sns

# load transaction file
filepath_transact = os.path.abspath(f"/Users/Sandbox/Data/transactions.csv")
df_sq = pd.read_csv(filepath_transact,encoding = "ISO-8859-1",sep=';')

# get asset holdings (function resides in stock_functions.py)
df_assets = getAssetHoldings(df_sq)
print('Assets:', '\n',df_assets,'\n')

#_init.py:
from .stock_functions import *
from .utility_functions import *
print('hello')

#stock_functions.py:
import pandas as pd
import yfinance as yf
import pandas_market_calendars as mcal

def getAssetHoldings(df):
    df_numberAssets_k = df_transactions[df_transactions['Transaktionen'].isin(['Buy'])]
    df_numberAssets_k = df_numberAssets_k[['Symbol','Quantity']]
    df_numberAssets_v = df_transactions[df_transactions['Transaktionen'].isin(['Sell'])]
    df_numberAssets_v = df_numberAssets_k[['Symbol','Quantity']]
    ....
    return df_current_assets 

我尝试了几次重启内核并导入库和函数。