docstr: returns best affine for given frame of data
docstr_tok: ["returns","best","affine","for","given","frame","of","data"]
code: def get_frame_affine(self, frame=0):
      """returns best affine for given frame of data"""
      subhdr = self.subheaders[frame]
      x_off = subhdr["x_offset"]
      y_off = subhdr["y_offset"]
      z_off = subhdr["z_offset"]
  
      zooms = self.get_zooms(frame=frame)
  
      dims = self.get_shape(frame)
      # get translations from center of image
      origin_offset = (np.array(dims) - 1) / 2.0
      aff = np.diag(zooms)
      aff[:3, -1] = -origin_offset * zooms[:-1] + np.array(
          [x_off, y_off, z_off]
      )
      return aff
  
imports: import warnings
  from numbers import Integral
  import numpy
  from .arraywriters import make_array_writer
  from .fileslice import canonical_slicers, predict_shape, slice2outax
  from .spatialimages import SpatialHeader, SpatialImage
  from .volumeutils import array_from_file, make_dt_codes, native_code, swapped_code
  from .wrapstruct import WrapStruct
label_desc: Use image node_id 5 for calling the EcatSubHeader obj's underlying member method code with example usage: obj.get_frame_affine(frame) and returns: aff