[CRASH CONDITION] - Guard self.unit against None

[VbhvGupta]

schedule/schedule/__init__.py

Line 305 in 82a43db

self.unit[:-1] if self.interval == 1 else self.unit,

• If self.interval == 1 is True, and, self.unit is None (which is what its being initialized to here) :

  schedule/schedule/__init__.py

  Line 232 in 3863eff

  self.unit: Optional[str] = None

  
  It results in crash.

• The code should guard against self.unit being None before attempting self.unit[:-1]