(self, lit, cls)
return cls in self.sentinels[lit]
Check if a literal is a sentinel of a given clause.

        Examples
        ========

        >>> from sympy.logic.algorithms.dpll2 import SATSolver
        >>> l = SATSolver([set([2, -3]), set([1]), set([3, -3]), set([2, -2]),
        ... set([3, -2])], set([1, 2, 3]), set([]))
        >>> l._find_model()
        True

        >>> l._is_sentinel(2, 3)
        True
        >>> l._is_sentinel(-3, 1)
        False
Check if a literal is a sentinel of a given clause.
Check if a literal is a sentinel of a given clause .
def _is_sentinel(self, lit, cls):
        """Check if a literal is a sentinel of a given clause.

        Examples
        ========

        >>> from sympy.logic.algorithms.dpll2 import SATSolver
        >>> l = SATSolver([set([2, -3]), set([1]), set([3, -3]), set([2, -2]),
        ... set([3, -2])], set([1, 2, 3]), set([]))
        >>> l._find_model()
        True

        >>> l._is_sentinel(2, 3)
        True
        >>> l._is_sentinel(-3, 1)
        False
        """
        return cls in self.sentinels[lit]
def _is_sentinel ( self , lit , cls ) : return cls in self . sentinels [ lit ]