code: def _process_span_annotations_for_word(annotations: List[str],
                                             span_labels: List[List[str]],
                                             current_span_labels: List[Optional[str]]) -> None:
          
          for annotation_index, annotation in enumerate(annotations):
              # strip all bracketing information to
              # get the actual propbank label.
              label = annotation.strip("()*")
  
              if "(" in annotation:
                  # Entering into a span for a particular semantic role label.
                  # We append the label and set the current span for this annotation.
                  bio_label = "B-" + label
                  span_labels[annotation_index].append(bio_label)
                  current_span_labels[annotation_index] = label
              elif current_span_labels[annotation_index] is not None:
                  # If there's no '(' token, but the current_span_label is not None,
                  # then we are inside a span.
                  bio_label = "I-" + current_span_labels[annotation_index]
                  span_labels[annotation_index].append(bio_label)
              else:
                  # We're outside a span.
                  span_labels[annotation_index].append("O")
              # Exiting a span, so we reset the current span label for this annotation.
              if ")" in annotation:
                  current_span_labels[annotation_index] = None
docs: Given a sequence of different label types for a single word and the current
          span label we are inside, compute the BIO tag for each label and append to a list.
  
          Parameters
          ----------
          annotations: ``List[str]``
              A list of labels to compute BIO tags for.
          span_labels : ``List[List[str]]``
              A list of lists, one for each annotation, to incrementally collect
              the BIO tags for a sequence.
          current_span_labels : ``List[Optional[str]]``
              The currently open span per annotation type, or ``None`` if there is no open span.