code: def from_file_map(klass, file_map):
      with file_map["image"].get_prepare_fileobj("rb") as fobj:
          arr = np.load(fobj)
      return klass(arr)
  
imports: import warnings
  from itertools import product
  import numpy
  import pytest
  from ..filebasedimages import FileBasedHeader, FileBasedImage, SerializableImage
  from .test_image_api import GenericImageAPI, SerializeMixin
label_desc: Use image node_id 6 for calling the FBNumpyImage obj's underlying member method code with example usage: obj.from_file_map(klass, file_map) and returns: klass