code: def round_bvals(bvals, bmag=None):
      """ "This function rounds the b-values
  
      Parameters
      ----------
      bvals : ndarray
          Array containing the b-values
  
      bmag : int
          The order of magnitude to round the b-values. If not given b-values
          will be rounded relative to the order of magnitude
          $bmag = (bmagmax - 1)$, where bmaxmag is the magnitude order of the
          larger b-value.
  
      Returns
      -------
      rbvals : ndarray
          Array containing the rounded b-values
      """
      if bmag is None:
          bmag = int(np.log10(np.max(bvals))) - 1
  
      b = bvals / (10**bmag)  # normalize b units
      return b.round() * (10**bmag)
  
imports: import logging
  from warnings import warn
  import numpy
  from scipy.linalg import inv, polar
  from dipy.io import gradients
  from dipy.core.onetime import auto_attr
  from dipy.core.geometry import vector_norm, vec2vec_rotmat
  from dipy.core.sphere import disperse_charges, HemiSphere
  from dipy.utils.deprecator import deprecate_with_version
label_desc: Use image node_id 11 for calling a global function with example usage: round_bvals(bvals, bmag) and returns: unknown