code: def as_affine(self, dtype="double"):
      T = to_matrix44(self._vec12, dtype=dtype)
      if not self._direct:
          T[:3, :3] *= -1
      return T
  
imports: import numpy
  import scipy.linalg
  from nibabel.affines import apply_affine
  from transforms3d.quaternions import mat2quat, quat2axangle
  from .transform import Transform
label_desc: Use image node_id 17 for calling the Affine obj's underlying member method code with example usage: obj.as_affine(dtype) and returns: T