def updateTracker(idx,newChar,tracker,force=False):
	"""Set final sequence value by column index if 'None'. 
	Optionally force overwrite of previously updated base."""
	if tracker[idx].base and force:
		# Note: Add alert when overwriting a previously set base
		tracker[idx] = tracker[idx]._replace(base=newChar)
	elif not tracker[idx].base:
		tracker[idx] = tracker[idx]._replace(base=newChar)
	return tracker