def get_constraints(self):
        """
        Retrieve all of the relevant constraints, aggregated from the pipfile, resolver,
        and parent dependencies and their respective conflict resolution where possible.

        :return: A set of **InstallRequirement** instances representing constraints
        :rtype: Set
        """
        constraints = {
            c for c in self.resolver.parsed_constraints
            if c and c.name == self.entry.name
        }
        pipfile_constraint = self.get_pipfile_constraint()
        if pipfile_constraint:
            constraints.add(pipfile_constraint)
        return constraints