def unreachable(self, completed, failed=None):
        """return whether this dependency has become impossible."""
        if len(self) == 0:
            return False
        against = set()
        if not self.success:
            against = completed
        if failed is not None and not self.failure:
            against = against.union(failed)
        if self.all:
            return not self.isdisjoint(against)
        else:
            return self.issubset(against)
def unreachable(self, completed, failed=None):
        
        if len(self) == 0:
            return False
        against = set()
        if not self.success:
            against = completed
        if failed is not None and not self.failure:
            against = against.union(failed)
        if self.all:
            return not self.isdisjoint(against)
        else:
            return self.issubset(against)
def unreachable ( self , completed , failed = None ) : if len ( self ) == 0 : return False against = set ( ) if not self . success : against = completed if failed is not None and not self . failure : against = against . union ( failed ) if self . all : return not self . isdisjoint ( against ) else : return self . issubset ( against )
return whether this dependency has become impossible.
return whether this dependency has become impossible .