# Buggy code
def create_userdata_dir(directory: str, create_dir=False) -> Path:
    """
    Create userdata directory structure.
    if create_dir is True, then the parent-directory will be created if it does not exist.
    Sub-directories will always be created if the parent directory exists.
    Raises OperationalException if given a non-existing directory.
    :param directory: Directory to check
    :param create_dir: Create directory if it does not exist.
    :return: Path object containing the directory
    """
    sub_dirs = [
        "backtest_results",
        "data",
        "hyperopts",
        "hyperopt_results",
        "notebooks",
        "plot",
        "strategies",
    ]
    folder = Path(directory)
    if not folder.is_dir():
        if create_dir:
            folder.mkdir(parents=True)
            logger.info(f"Created user-data directory: {folder}")
        else:
            raise OperationalException(
                f"Directory `{folder}` does not exist. "
                "Please use `freqtrade create-userdir` to create a user directory"
            )

    # Create required subdirectories
    for f in sub_dirs:
        subfolder = folder / f
        if not subfolder.is_dir():
            subfolder.mkdir(parents=False)
    return folder


# Traceback (Exception)
2020-02-20 22:47:28,025 - freqtrade - ERROR - Fatal exception!
Traceback (most recent call last):
File "/opt/tradebot/freqtrade/.env/lib/python3.7/site-packages/talib/__init__.py", line 20, in wrapper
for arg in chain(args, kwargs.values())
StopIteration

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/freqtrade/freqtrade/main.py", line 36, in main
return_code = args['func'](args)
File "/freqtrade/freqtrade/commands/optimize_commands.py", line 76, in start_hyperopt
hyperopt.start()
File "/freqtrade/freqtrade/optimize/hyperopt.py", line 488, in start
preprocessed = self.backtesting.strategy.tickerdata_to_dataframe(data)
File "/freqtrade/freqtrade/strategy/interface.py", line 448, in tickerdata_to_dataframe
for pair, pair_data in tickerdata.items()}
File "/freqtrade/freqtrade/strategy/interface.py", line 448, in <dictcomp>
for pair, pair_data in tickerdata.items()}
File "/freqtrade/freqtrade/strategy/interface.py", line 464, in advise_indicators
return self.populate_indicators(dataframe, metadata)
File "/freqtrade/user_data/strategies/MyDev.py", line 205, in populate_indicators
dataframe['mfi'] = ta.MFI(dataframe)
File "talib/_abstract.pxi", line 352, in talib._ta_lib.Function.__call__
File "talib/_abstract.pxi", line 383, in talib._ta_lib.Function.__call_function
File "/opt/tradebot/freqtrade/.env/lib/python3.7/site-packages/talib/__init__.py", line 24, in wrapper
return func(*args, **kwargs)
File "talib/_func.pxi", line 8454, in talib._ta_lib.MFI
Exception: volume is not double

# Fixed code
def create_userdata_dir(directory: str, create_dir: bool = False) -> Path:
    """
    Create userdata directory structure.
    if create_dir is True, then the parent-directory will be created if it does not exist.
    Sub-directories will always be created if the parent directory exists.
    Raises OperationalException if given a non-existing directory.
    :param directory: Directory to check
    :param create_dir: Create directory if it does not exist.
    :return: Path object containing the directory
    """
    sub_dirs = [
        "backtest_results",
        "data",
        "hyperopts",
        "hyperopt_results",
        "notebooks",
        "plot",
        "strategies",
    ]
    folder = Path(directory)
    if not folder.is_dir():
        if create_dir:
            folder.mkdir(parents=True)
            logger.info(f"Created user-data directory: {folder}")
        else:
            raise OperationalException(
                f"Directory `{folder}` does not exist. "
                "Please use `freqtrade create-userdir` to create a user directory"
            )

    # Create required subdirectories
    for f in sub_dirs:
        subfolder = folder / f
        if not subfolder.is_dir():
            subfolder.mkdir(parents=False)
    return folder