code: def mean_orientation(xyz):
      """
      Calculates the mean orientation of a curve
  
      Parameters
      ----------
      xyz : array-like shape (N,3)
         array representing x,y,z of N points in a curve
  
      Returns
      -------
      m : float
          Mean orientation.
      """
      xyz = np.asarray(xyz)
      n_pts = xyz.shape[0]
      if n_pts == 0:
          raise ValueError("xyz array cannot be empty")
  
      dxyz = np.gradient(xyz)[0]
  
      return np.mean(dxyz, axis=0)
  
imports: from dipy.utils.deprecator import deprecate_with_version
  from dipy.tracking.streamline import set_number_of_points
  import numpy
  from scipy.interpolate import splprep, splev
label_desc: Use image node_id 10 for calling a global function with example usage: mean_orientation(xyz) and returns: np