code: @Nullable
    public Object get(@Nonnull FieldPath fieldPath) {
      Value value = extractField(fieldPath);
  
      if (value == null) {
        return null;
      }
  
      Object decodedValue = decodeValue(value);
      return convertToDateIfNecessary(decodedValue);
    }
docs: Returns the value at the field or null if the field doesn't exist.
  
  @param fieldPath The path to the field.
  @return The value at the given field or null.