code: def isunit(q):
      """Return True is this is very nearly a unit quaternion"""
      return np.allclose(norm(q), 1)
  
file_path: nibabel/nibabel/quaternions.py
imports: import math
  import numpy
  from .casting import sctypes
label_desc: Use image node_id 7 for calling a global function with example usage: isunit(q) and returns: np