Does an attorney have a duty to conduct adequate legal research prior to filing a complaint?

the attorney has a duty prior to filing a complaint not only to conduct a reasonable factual investigation, but also to perform adequate legal research that confirms whether the theoretical underpinnings of the complaint are warranted by existing law or a good faith argument for an extension, modification or reversal of existing law. One of the fundamental purposes of Rule 11 is to reduce frivolous claims, defenses or motions and to deter costly meritless maneuvers, thereby avoiding delay and unnecessary expense in litigation.

Christian v. Mattel, Inc., 286 F. 3d 1118, 1127 (9th Cir. 2002) (quotation and citations omitted).