def checked_spec_clauses(self, *args, **kwargs):
    'Wrap a call to spec clauses into a try/except block that raise\n        a comprehensible error message in case of failure.\n        '
    requestor = kwargs.pop('required_from', None)
    try:
        clauses = self.spec_clauses(*args, **kwargs)
    except RuntimeError as exc:
        msg = str(exc)
        if requestor:
            msg += ' [required from package "{0}"]'.format(requestor)
        raise RuntimeError(msg)
    return clauses
Wrap a call to spec clauses into a try/except block that raise
a comprehensible error message in case of failure.
def checked_spec_clauses(self, *args, **kwargs):
    'Wrap a call to spec clauses into a try/except block that raise\n        a comprehensible error message in case of failure.\n        '
    requestor = kwargs.pop('required_from', None)
    try:
        clauses = self.spec_clauses(*args, **kwargs)
    except RuntimeError as exc:
        msg = str(exc)
        if requestor:
            msg += ' [required from package "{0}"]'.format(requestor)
        raise RuntimeError(msg)
    return clauses