Add LUKE (#11223)

* Rebase with master

* Minor bug fix in docs

* Copy files from adding_luke_v2 and improve docs

* change the default value of use_entity_aware_attention to True

* remove word_hidden_states

* fix head models

* fix tests

* fix the conversion script

* add integration tests for the pretrained large model

* improve docstring

* Improve docs, make style

* fix _init_weights for pytorch 1.8

* improve docs

* fix tokenizer to construct entity sequence with [MASK] entity when entities=None

* Make fix-copies

* Make style & quality

* Bug fixes

* Add LukeTokenizer to init

* Address most comments by @patil-suraj and @LysandreJik

* rename _compute_extended_attention_mask to get_extended_attention_mask

* add comments to LukeSelfAttention

* fix the documentation of the tokenizer

* address comments by @patil-suraj, @LysandreJik, and @sgugger

* improve docs

* Make style, quality and fix-copies

* Improve docs

* fix docs

* add "entity_span_classification" task

* update example code for LukeForEntitySpanClassification

* improve docs

* improve docs

* improve the code example in luke.rst

* rename the classification layer in LukeForEntityClassification from typing to classifier

* add bias to the classifier in LukeForEntitySpanClassification

* update docs to use fine-tuned hub models in code examples of the head models

* update the example sentences

* Make style & quality

* Add require_torch to tokenizer tests

* Add require_torch to tokenizer tests

* Address comments by @sgugger and add community notebooks

* Make fix-copies

Co-authored-by: Ikuya Yamada <ikuya@ikuya.net>

src/transformers/tokenization_utils_base.py

@@ -801,7 +801,9 @@ class SpecialTokensMixin:
             if key in self.SPECIAL_TOKENS_ATTRIBUTES:
                 if key == "additional_special_tokens":
                     assert isinstance(value, (list, tuple)), f"Value {value} is not a list or tuple"
-                    assert all(isinstance(t, str) for t in value), "One of the tokens is not a string"
+                    assert all(
+                        isinstance(t, (str, AddedToken)) for t in value
+                    ), "One of the tokens is not a string or an AddedToken"
                     setattr(self, key, value)
                 elif isinstance(value, (str, AddedToken)):
                     setattr(self, key, value)