in pystemd/systemd1/unit_signatures.py [0:0]
def signature_array(properties):
args = [(ord(b"a"), b"(sv)")]
for prop_name, prop_value in properties.items():
prop_name = x2char_star(prop_name)
signature = KNOWN_UNIT_SIGNATURES[prop_name]
if callable(signature):
prop_name, signature, prop_value = signature(prop_name, prop_value)
args += [(ord(b"r"), b"sv"), (ord(b"s"), prop_name)]
args += [(ord(b"v"), signature)]
args += apply_signature(signature, [prop_value])
args += [(-1, None), (-1, None)]
args += [(-1, None)]
return args