convert_npy fails silently if no .npy files are found

[anweiteck]

See TODO, line 24:

nano-oscillator/analysis/geom.py

Lines 12 to 37 in 6452a73

	def convert_npy(date: str = None):
	"""Converts all .npy files to .tsv files."""
	date = date if date is not None else paths.top.latest_date()
	conversion = ["x", "y", "z"]
	for file in os.listdir(paths.data.raw(date)):
	fields = {}
	if file.endswith(".npy"):
	#TODO: raise FileNotFoundError
	filename = os.path.splitext(file)[0]
	write.prep_dir(paths.spatial.geom_dir(filename, date))
	fields[filename] = np.load(os.path.join(paths.data.raw(date), file))
	for component_index in range(len(fields[filename])):
	component = conversion[component_index]
	for z_index in range(len(fields[filename][component_index])):
	pd.DataFrame(np.flip(fields[filename][component_index][z_index])) \
	.to_csv(paths.spatial.spatial_path(
	filename, component, z_index, date), sep="\t", index=False
	)