code: def _checkangles(angles, axis=None):
      """Internal function to check that angles are in radians."""
      msg = (
          "Angles are not in unit of radians. Please use the "
          "`pingouin.convert_angles` function to map your angles to "
          "the [-pi, pi] range."
      )
      ptp_rad = np.nanmax(angles, axis=axis) - np.nanmin(
          angles, axis=axis
      )
      ptp_mask = ptp_rad <= 2 * np.pi
      if not ptp_mask.all():
          raise ValueError(msg)
  
file_path: pingouin/pingouin/circular.py
imports: import numpy
  from scipy.stats import norm
  from .utils import remove_na
label_desc: Use image node_id 1 for calling a global function with example usage: _checkangles(angles, axis) without return types