What is the test for determining whether "exceptional and extremely unusual hardship" is present for the purpose of cancellation of removal?

We lack jurisdiction to review the agency's "determination of whether exceptional and extremely unusual hardship is present for the purposes of cancellation of removal . . ., except in those rare cases where the BIA decision on whether this kind of hardship exists is made without rational justification or based on an erroneous legal standard, or rests on fact-finding which is flawed by an error of law." Mendez v. Holder, 566 F.3d 316, 322 (2d Cir. 2009) (internal quotation marks and citations omitted). However, we retain jurisdiction to review constitutional claims and "questions of law." 8 U.S.C. 1252(a)(2)(D). We lack jurisdiction to review any legal argument that "does not even reach the level of being colorable." Barco-Sandoval v. Gonzales, 516 F.3d 35, 40 (2d Cir. 2008).