Add missing flags for pretrain experiment (AttributeError)

tapas/experiments/tapas_pretraining_experiment.py

@@ -27,6 +27,18 @@
 
 FLAGS = flags.FLAGS
 
+flags.DEFINE_integer(
+    "restrict_attention_bucket_size", 0, "For sparse attention modes, further "
+    "restrict attention to consecutive buckets of uniform size.")
+
+flags.DEFINE_integer(
+    "restrict_attention_header_size", None, "For sparse attention modes, size "
+    "of the first section that will attend to/from everything else.")
+
+flags.DEFINE_float(
+    "restrict_attention_row_heads_ratio", 0.5, "For sparse attention modes, "
+    "proportion of heads that should focus on rows vs columns.")
+
 flags.DEFINE_string("data_format", "tfrecord", "The input data format.")
 
 flags.DEFINE_string(