Assign local variable. The line processed looked somewhat like this:
        variable = some_call()

def set_local(self, value, variable_name):
        '''
        Assign local variable. The line processed looked somewhat like this:
        variable = some_call()
        '''
        self.log('assigning %s = %r', variable_name, value)
        self._locals[variable_name] = value
        return value