def read_annotation_file(filename):
"""Loads a file annotated for co-references with brat."""
annotations = Annotations(filename, read_only=True)
entities = {entity.id: entity for entity in annotations.get_entities()
if entity.type in ('Actor', 'Location')}
relations = defaultdict(list)
for relation in annotations.get_relations():
relations[relation.arg1].append(relation.arg2)
chains = resolve(relations, entities)
actors, locations = [], []
for chain in chains:
chain = [(entity, entities[entity].tail.strip(),
entities[entity].get_start(),
entities[entity].get_end()) for entity in chain]
entity_type = entities[chain[0][0]].type
if entity_type == 'Actor':
actors.append(chain)
elif entity_type == 'Location':
locations.append(chain)
return actors, locations, entities
