class_docstr: Class for AFNI header
code: def from_header(klass, header=None):
      if header is None:
          raise AFNIHeaderError(
              "Cannot create AFNIHeader from nothing."
          )
      if type(header) == klass:
          return header.copy()
      raise AFNIHeaderError(
          "Cannot create AFNIHeader from non-AFNIHeader."
      )
  
imports: import os
  import re
  from copy import deepcopy
  import numpy
  from .arrayproxy import ArrayProxy
  from .fileslice import strided_scalar
  from .spatialimages import HeaderDataError, ImageDataError, SpatialHeader, SpatialImage
  from .volumeutils import Recoder
label_desc: Use image node_id 2 for calling the AFNIHeader obj's underlying member method code with example usage: obj.from_header(klass, header) and returns: header