What is the test for a plaintiff to prove that his actions were retaliatory against a prison officer?

Rhodes v. Robinson, 408 F.3d 559, 567-68 (9th Cir.2005); accord Brodheim v. Cry, 584 F.3d 1262, 1269 (9th Cir.2009). The court must "'afford appropriate deference and flexibility' to prison officials in the evaluation of proffered legitimate penological reasons for conduct alleged to be retaliatory." Pratt v. Rowland, 65 F.3d 802, 807 (9th Cir.1995) (quoting Sandin v. Conner, 515 U.S. 472, 482, 115 S.Ct. 2293, 132 L.Ed.2d 418 (1995)). The burden is on plaintiff to demonstrate "that there were no legitimate correctional purposes motivating the actions he complains of." Pratt, 65 F.3d at 808.