code: def _ch_helper(gamma, s, r, h, p0, p1, x):
      """Helper function for generating picklable cubehelix colormaps."""
      # Apply gamma factor to emphasise low or high intensity values
      xg = x**gamma
      # Calculate amplitude and angle of deviation from the black to white
      # diagonal in the plane of constant perceived intensity.
      a = h * xg * (1 - xg) / 2
      phi = 2 * np.pi * (s / 3 + r * x)
      return xg + a * (p0 * np.cos(phi) + p1 * np.sin(phi))
  
imports: from functools import partial
  import numpy
label_desc: Use image node_id 7 for calling a global function with example usage: _ch_helper(gamma, s, r, h, p0, p1, x) and returns: unknown