code: def _circfunc(samples, high, low, skipna):
      samples = np.asarray(samples)
      if skipna:
          samples = samples[~np.isnan(samples)]
      if samples.size == 0:
          return np.nan
      return _angle(samples, low, high, np.pi)
  
imports: import warnings
  from collections.abc import Sequence
  from copy import copy
  from copy import deepcopy
  import numpy
  import pandas
  from scipy.fftpack import next_fast_len
  from scipy.interpolate import CubicSpline
  from scipy.stats.mstats import mquantiles
  from xarray import apply_ufunc
  from ..None import _log
  from ..utils import conditional_jit, conditional_vect, conditional_dask
  from .density_utils import histogram
label_desc: Use image node_id 13 for calling a global function with example usage: _circfunc(samples, high, low, skipna) and returns: _angle, np