'remove an annotation for a project'

def update_annotation(self, key, value):

    annos = (self.get(Project.annotations_path) or {})
    if (not annos):
        return True
    updated = False
    anno = self.find_annotation(key)
    if anno:
        annos[(Project.annotation_prefix + key)] = value
        updated = True
    else:
        self.add_annotations({(Project.annotation_prefix + key): value})
    return updated
