<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_constraint(self, pkge=None, constr=None):
 """ Checks the constraints. :param pkge: the package to check :type pkge: Package :param constr: the package constraint to check :type constr: PackageConstraint """

        if not pkge is None:
            return javabridge.call(
                self.jobject, "checkConstraint", "(Lweka/core/packageManagement/Package;)Z", pkge.jobject)
        if not constr is None:
            return javabridge.call(
                self.jobject, "checkConstraint", "(Lweka/core/packageManagement/PackageConstraint;)Z", pkge.jobject)
        raise Exception("Either package or package constraing must be provided!")