[ENH] Fill nan when generating RKMESpecification

examples/examples1/example_rkme.py

@@ -4,6 +4,8 @@ import learnware.specification as specification
 
 if __name__ == "__main__":
     data_X = np.random.randn(10000, 20)
+    for i in range(10):
+        data_X[i, i] = np.nan
     spec1 = specification.utils.generate_rkme_spec(X=data_X, gamma=0.1, cuda_idx=-1)
     spec2 = specification.rkme.RKMESpecification()
     spec1.generate_stat_spec_from_data(data_X)