def __sub__(self, value):
if type(value) in [int, float]:
base_variable = composition_sequence_from_value([self._state],
self._state)[-1]
if base_variable._arithmetic_build:
self._state._arithmetic_stack.append(
formula_tree.ArithmeticSubtract(value))
return self
else:
raise Exception(
"Value subtracted from quantity %s must be of type int or float."
% self)
def __sub__(self, value):
if self._state._arithmetic_build:
self._state._arithmetic_stack.append(
formula_tree.ArithmeticSubtract(value))
return self