Is a plaintiff entitled to attorney fees in an action to enforce section 1983 of Section 42 of the United States Code?

Title 42, section 1988, of the United States Code provides in part that a court may in its discretion allow the prevailing party reasonable attorney fees in any action to enforce a provision of section 1983. Where, as here, the prevailing party is a defendant, attorney fees are awarded only where the " 'claim was frivolous, unreasonable, or groundless, or . . . the plaintiff continued to litigate after it clearly became so.' " (Hughes v. Rowe (1980) 449 U.S. 5, 15 [66 L.Ed.2d 163, 173].)