code: def alpha_colormap(color, min_alpha=40, max_alpha=255, N=256):
      """
      Generate a transparency-based monochromatic colormap.
  
      Parameters
      ----------
      color : str or tuple
          Color name, hex code or RGB tuple.
      min_alpha, max_alpha: int
          Values between 0 - 255 representing the range of alpha values to use for
          colormapped pixels that contain data.
  
      Returns
      -------
      :class:`matplotlib.colors.LinearSegmentedColormap`
  
      """
      for a in (min_alpha, max_alpha):
          if a < 0 or a > 255:
              raise ValueError(
                  "Alpha values must be integers between 0 and 255"
              )
      r, g, b = mpl.colors.to_rgb(color)
      return mpl.colors.LinearSegmentedColormap(
          "_datashader_alpha",
          {
              "red": [(0.0, r, r), (1.0, r, r)],
              "green": [(0.0, g, g), (1.0, g, g)],
              "blue": [(0.0, b, b), (1.0, b, b)],
              "alpha": [
                  (0.0, min_alpha / 255, min_alpha / 255),
                  (1.0, max_alpha / 255, max_alpha / 255),
              ],
          },
          N=N,
      )
  
imports: import warnings
  from matplotlib.image import _ImageBase
  from matplotlib.patches import Patch
  from matplotlib.transforms import Bbox, TransformedBbox, BboxTransform
  import matplotlib
  import numpy
  from .None import reductions
  from .None import transfer_functions
  from .colors import Sets1to3
  from .core import bypixel, Canvas
label_desc: Use image node_id 5 for calling a global function with example usage: alpha_colormap(color, min_alpha, max_alpha, N) and returns: mpl