Numerous courts also have recognized two 'implicit' prerequisites: 1) that the class definition is drafted to ensure that membership is 'capable of ascertainment under some objective standard;' and 2) that all class representatives are in fact members of the proposed class. See, e.g., Fournigault v. Independence One Mortgage Corp., 234 F.R.D. 641, 644-45 (N.D.Ill. 2006); Liles v. Am. Corrective Counseling Servs., 231 F.R.D. 565, 571 (S.D. Iowa 2005); Dumas v. Albers Med., Inc., No. 03-0640-CV-W-GAF, 2005 U.S. Dist. LEXIS 33482, 2005 WL 2172030, at *5 (W.D. Mo. Sept. 7, 2005); Elizabeth M. v. Ross, No. 8:02CV585, 2005 U.S. Dist. LEXIS 45107, 2005 WL 1206150, at *2 (D. Neb. May 11, 2005) (recognizing both additional factors as necessary to certification of class); rev'd on other grounds, 458 F.3d 779 (8th Cir. 2006); McElhaney v. Eli Lilly & Co., 93 F.R.D. 875, 877 (D.S.D. 1982); see also see also Roman v. ESB, Inc., 550 F.2d 1343, 1348 (4th Cir. 1976) ('[T]he definition of the class is an essential prerequisite to maintaining a class action.'); Carson P. ex rel. Foreman v. Heineman, 240 F.R.D. 456, 495-502 (D. Neb. 2007) (recognizing that 'class should be clearly defined at the ...