feat(medcat): CU-869azdc7x: Dynamic imports for legacy conversion (#198)

* CU-869azdc7x: Import DeID stuff in a dynamic way for conversion

* CU-869azdc7x: Import RelCAT stuff in a dynamic way for conversion

* CU-869azdc7x: Fix some whitespace stuff

* CU-869azdc7x: Import MetaCAT stuff in a dynamic way for conversion

* CU-869azdc7x: Use fewer protected fields

Author: mart-r

medcat-v2/medcat/utils/legacy/conversion_all.py

@@ -11,9 +11,6 @@
 from medcat.utils.legacy.convert_cdb import get_cdb_from_old
 from medcat.utils.legacy.convert_config import get_config_from_old
 from medcat.utils.legacy.convert_vocab import get_vocab_from_old
-from medcat.utils.legacy.convert_meta_cat import get_meta_cat_from_old
-from medcat.utils.legacy.convert_rel_cat import get_rel_cat_from_old
-from medcat.utils.legacy.convert_deid import get_trf_ner_from_old
 from medcat.utils.legacy.helpers import fix_subnames
 
 
@@ -85,40 +82,47 @@ def convert(self) -> CAT:
         cat = CAT(cdb, vocab, config)
         fix_subnames(cat)
         # MetaCATs
-        meta_cats = [
-            get_meta_cat_from_old(
-                os.path.join(self.old_model_folder, subfolder),
-                cat._pipeline.tokenizer)
+        meta_cat_folders = [
+            os.path.join(self.old_model_folder, subfolder)
             for subfolder in os.listdir(self.old_model_folder)
             if subfolder.startswith("meta_")
         ]
-        for mc in meta_cats:
-            cat.add_addon(mc)
+        if meta_cat_folders:
+            from medcat.utils.legacy.convert_meta_cat import (
+                get_meta_cat_from_old)
+            for subfolder in meta_cat_folders:
+                mc = get_meta_cat_from_old(subfolder, cat.pipe.tokenizer)
+                cat.add_addon(mc)
 
         # RelCATs
-        rel_cats = [
-            get_rel_cat_from_old(
-                cdb,
-                os.path.join(self.old_model_folder, subfolder),
-                cat._pipeline.tokenizer)
+        rel_cats_folders = [
+            os.path.join(self.old_model_folder, subfolder)
             for subfolder in os.listdir(self.old_model_folder)
             if subfolder.startswith("rel_")
         ]
-        for rc in rel_cats:
-            cat.add_addon(rc)
+        if rel_cats_folders:
+            from medcat.utils.legacy.convert_rel_cat import (
+                get_rel_cat_from_old)
+            for subfolder in rel_cats_folders:
+                rel_cat = get_rel_cat_from_old(
+                    cdb, subfolder, cat.pipe.tokenizer)
+                cat.add_addon(rel_cat)
 
         # DeID / TransformersNER
-        trf_ners = [
-            get_trf_ner_from_old(
-                os.path.join(self.old_model_folder, subfolder),
-                cat._pipeline.tokenizer)
+        trf_folders = [
+            os.path.join(self.old_model_folder, subfolder)
             for subfolder in os.listdir(self.old_model_folder)
             if subfolder.startswith("trf_")
         ]
-        if len(trf_ners) > 1:
-            raise ValueError("Cannot use more than 1 tranformers NER. "
-                             f"Got {len(trf_ners)}")
-        if trf_ners:
+        if trf_folders:
+            from medcat.utils.legacy.convert_deid import get_trf_ner_from_old
+            trf_ners = [
+                get_trf_ner_from_old(subfolder, cat.pipe.tokenizer)
+                for subfolder in os.listdir(self.old_model_folder)
+            ]
+            if len(trf_ners) > 1:
+                raise ValueError("Cannot use more than 1 tranformers NER. "
+                                 f"Got {len(trf_ners)}")
             logger.info("Found a Transformers based NER component "
                         "- probably for DeID")
             trf_ner = trf_ners[0]
@@ -132,20 +136,20 @@ def convert(self) -> CAT:
             # replace component in pipeline
             # get the index of component in list
             index = next((c_num for c_num, comp in
-                          enumerate(cat._pipeline._components)
+                          enumerate(cat.pipe._components)
                           if comp.get_type() is CoreComponentType.ner))
             # set / change / replace the NER component
             logger.info(f"Changing the NER component in the pipe to {trf_ner}")
-            cat._pipeline._components[index] = trf_ner
+            cat.pipe._components[index] = trf_ner
             # replace linker to no-action linker
             config.components.linking.comp_name = 'no_action'
             index_link = next(
-                (c_num for c_num, comp in enumerate(cat._pipeline._components)
+                (c_num for c_num, comp in enumerate(cat.pipe._components)
                  if comp.get_type() is CoreComponentType.linking))
             # set / change / replace Linker to no-action linker
             logger.info("Changing the linking component in the pipe to a "
                         "no-action linker")
-            cat._pipeline._components[index_link] = NoActionLinker()
+            cat.pipe._components[index_link] = NoActionLinker()
 
         if self.new_model_folder:
             logger.info("Saving converted model to '%s'",