code: def conjugate(q):
      """Conjugate of quaternion
  
      Parameters
      ----------
      q : 4 element sequence
         w, i, j, k of quaternion
  
      Returns
      -------
      conjq : array shape (4,)
         w, i, j, k of conjugate of `q`
      """
      return np.array(q) * np.array([1.0, -1, -1, -1])
  
file_path: nibabel/nibabel/quaternions.py
imports: import math
  import numpy
  from .casting import sctypes
label_desc: Use image node_id 5 for calling a global function with example usage: conjugate(q) and returns: unknown