Very generic error message

[giovannipizzi]

Here, the error says cannot find Fermi energy:

aiida-wannier90-workflows/aiida_wannier90_workflows/utils/workflows/plot.py

Lines 255 to 258 in 8476014

	if workchain0.process_class == PwBandsWorkChain:
	fermi_energy = workchain0.outputs["scf_parameters"]["fermi_energy"]
	else:
	raise ValueError("Cannot find fermi energy")

In reality, it should say "The first parameter is not a PW Bands".
This will also help users debug (I had a user who swapped the two PKs and couldn't understand why)