def _check_keys(a, b: Resources):
if not set(a.keys()) == set(b.keys()):
raise ValueError(
'the same dimensions must be provided for both resources %r vs %r',
a.keys(), b.keys())
def sum_resources(a: Resources, b: Resources) -> Resources:
_check_keys(a, b)
c = {}
for resource in a.keys():
c[resource] = a[resource] + b[resource]
return c