<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def reduce_by(self, package_request):
 """Reduce this scope wrt a package request. Returns: A (_PackageScope, [Reduction]) tuple, where the scope is a new scope copy with reductions applied, or self if there were no reductions, or None if the scope was completely reduced. """

        self.solver.reduction_broad_tests_count += 1

        if self.package_request.conflict:
            # conflict scopes don't reduce. Instead, other scopes will be
            # reduced against a conflict scope.
            return (self, [])

        # perform the reduction
        new_slice, reductions = self.variant_slice.reduce_by(package_request)

        # there was total reduction
        if new_slice is None:
            self.solver.reductions_count += 1

            if self.pr:
                reqstr = _short_req_str(package_request)
                self.pr("%s was reduced to nothing by %s", self, reqstr)
                self.pr.br()

            return (None, reductions)

        # there was some reduction
        if new_slice is not self.variant_slice:
            self.solver.reductions_count += 1
            scope = self._copy(new_slice)

            if self.pr:
                reqstr = _short_req_str(package_request)
                self.pr("%s was reduced to %s by %s", self, scope, reqstr)
                self.pr.br()
            return (scope, reductions)

        # there was no reduction
        return (self, [])