code: public Codec<?> get(final BsonType bsonType) {
          Codec<?> codec = codecs[bsonType.getValue()];
          if (codec == null) {
              Class<?> clazz = bsonTypeClassMap.get(bsonType);
              if (clazz == null) {
                  throw new CodecConfigurationException(format("No class mapped for BSON type %s.", bsonType));
              } else {
                  throw new CodecConfigurationException(format("Can't find a codec for %s.", clazz));
              }
          }
          return codec;
      }
docs: Gets the Codec mapped to the given bson type.
  
  @param bsonType the non-null BsonType
  @return the non-null Codec