ModelChain.prepare_inputs press_temp can be unbound

[wholmgren]

The except block should set press_temp = {}. The kwarg should also be called as a kwarg.

pvlib-python/pvlib/modelchain.py

Lines 1352 to 1360 in 149fd02

	try:
	press_temp = _build_kwargs(['pressure', 'temp_air'],
	weather[0] if isinstance(weather, tuple)
	else weather)
	press_temp['temperature'] = press_temp.pop('temp_air')
	except KeyError:
	pass
	self._prep_inputs_solar_pos(press_temp)

[wholmgren]

This is not actually possible because the first line of the block always assigns at least press_temp = {}. Better style would be to move the first line out of the try block.