code: @Override
      public float getFloat(@NonNull String key) {
          if (key == null) { throw new IllegalArgumentException("key cannot be null."); }
  
          synchronized (lock) {
              return CBLConverter.asFloat(getMValue(internalDict, key), internalDict);
          }
      }
docs: Gets a property's value as an float.
  Integers will be converted to float. The value `true` is returned as 1.0, `false` as 0.0.
  Returns 0.0 if the value doesn't exist or does not have a numeric value.
  
  @param key the key
  @return the float value.