# Buggy code
def parse_timerange(text: Optional[str]):
    """
    Parse the value of the argument --timerange to determine what is the range desired
    :param text: value from --timerange
    :return: Start and End range period
    """
    if text is None:
        return TimeRange(None, None, 0, 0)
    syntax = [
        (r"^-(\d{8})$", (None, "date")),
        (r"^(\d{8})-$", ("date", None)),
        (r"^(\d{8})-(\d{8})$", ("date", "date")),
        (r"^-(\d{10})$", (None, "date")),
        (r"^(\d{10})-$", ("date", None)),
        (r"^(\d{10})-(\d{10})$", ("date", "date")),
        (r"^-(\d{13})$", (None, "date")),
        (r"^(\d{13})-$", ("date", None)),
        (r"^(\d{13})-(\d{13})$", ("date", "date")),
    ]
    for rex, stype in syntax:
        # Apply the regular expression to text
        match = re.match(rex, text)
        if match:  # Regex has matched
            rvals = match.groups()
            index = 0
            start: int = 0
            stop: int = 0
            if stype[0]:
                starts = rvals[index]
                if stype[0] == "date" and len(starts) == 8:
                    start = arrow.get(starts, "YYYYMMDD").timestamp
                elif len(starts) == 13:
                    start = int(starts) // 1000
                else:
                    start = int(starts)
                index += 1
            if stype[1]:
                stops = rvals[index]
                if stype[1] == "date" and len(stops) == 8:
                    stop = arrow.get(stops, "YYYYMMDD").timestamp
                elif len(stops) == 13:
                    stop = int(stops) // 1000
                else:
                    stop = int(stops)
            return TimeRange(stype[0], stype[1], start, stop)
    raise Exception('Incorrect syntax for timerange "%s"' % text)


# 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 parse_timerange(text: Optional[str]) -> "TimeRange":
    """
    Parse the value of the argument --timerange to determine what is the range desired
    :param text: value from --timerange
    :return: Start and End range period
    """
    if text is None:
        return TimeRange(None, None, 0, 0)
    syntax = [
        (r"^-(\d{8})$", (None, "date")),
        (r"^(\d{8})-$", ("date", None)),
        (r"^(\d{8})-(\d{8})$", ("date", "date")),
        (r"^-(\d{10})$", (None, "date")),
        (r"^(\d{10})-$", ("date", None)),
        (r"^(\d{10})-(\d{10})$", ("date", "date")),
        (r"^-(\d{13})$", (None, "date")),
        (r"^(\d{13})-$", ("date", None)),
        (r"^(\d{13})-(\d{13})$", ("date", "date")),
    ]
    for rex, stype in syntax:
        # Apply the regular expression to text
        match = re.match(rex, text)
        if match:  # Regex has matched
            rvals = match.groups()
            index = 0
            start: int = 0
            stop: int = 0
            if stype[0]:
                starts = rvals[index]
                if stype[0] == "date" and len(starts) == 8:
                    start = arrow.get(starts, "YYYYMMDD").timestamp
                elif len(starts) == 13:
                    start = int(starts) // 1000
                else:
                    start = int(starts)
                index += 1
            if stype[1]:
                stops = rvals[index]
                if stype[1] == "date" and len(stops) == 8:
                    stop = arrow.get(stops, "YYYYMMDD").timestamp
                elif len(stops) == 13:
                    stop = int(stops) // 1000
                else:
                    stop = int(stops)
            return TimeRange(stype[0], stype[1], start, stop)
    raise Exception('Incorrect syntax for timerange "%s"' % text)