[Python] How to safely access Optional[float] in Indie when value_or(None) gives type error?

I'm writing an indicator in the TakeProfit's Indie language, and I'm trying to plot a marker based on a value from a higher timeframe.

The value is declared as Optional[float], and I want to return a fallback value if it's not set. But I'm getting a confusing error about NoneType not matching float, even though I just want to check whether the optional has a value:

Here's a minimal version of my code:

# indie:lang_version = 5

from indie import indicator, plot, param, color, Optional, MainContext, TimeFrame, sec_context
from indie.plot import marker_style, marker_position, Marker

@sec_context
def HTF(self):
return 1.0

@indicator("Marker Bug - simplified", overlay_main_pane=False)
@param.bool("enabled", default=True)
@param.time_frame("htf", default="1D")
@plot.marker("m", style=marker_style.LABEL, position=marker_position.ABOVE)
class Main(MainContext):
def __init__(self, htf: TimeFrame) -> None:
self._val = Optional[float](None)

if htf != self.time_frame:
r = self.calc_on(HTF, time_frame=htf)
if r[0] > 0:
self._val = Optional[float](80.0)

def calc(self, enabled: bool, htf: TimeFrame):
return Marker(
self._val.value_or(20.0),
text="HTF!" if self._val.value_or(None) is not None else None,
color=color.GREEN
) if enabled else Marker(None)


This causes the error:

Error: 26:27 could not find function definition that matches self._val.value_or call, reason: pos arg 1 of <class 'NoneType'> type does not match with the param of type <class 'float'>
​

But I thought .value_or(...) is supposed to return the wrapped value or a fallback if it's None.

What’s the correct way to test and unwrap an Optional[float] for use in a Marker(...)?

Should I avoid passing None to value_or?

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