def check_constants(self):
        """Verify that all constant definitions evaluate to a value."""
        for constant in self.constants:
            try:
                self.lookup_constant(constant)
            except __HOLE__ as e:
                fmt = "Constant '{name}' is undefined"
                self.append_error(fmt, name=e.args[0])
            except:
                fmt = "Constant '{name}' has a circular reference"
                self.append_error(fmt, name=constant)
dataset/ETHPy150Open EricssonResearch/calvin-base/calvin/csparser/checker.py/Checker.check_constants