docs: def _make_cmap(colors, position=None, bit=False):
      '''
      _make_cmap takes a list of tuples which contain RGB values. The RGB
      values may either be in 8-bit [0 to 255] (in which bit must be set to
      True when called) or arithmetic [0 to 1] (default). _make_cmap returns
      a cmap with equally spaced colors.
      Arrange your tuples so that the first color is the lowest value for the
      colorbar and the last is the highest.
      position contains values from 0 to 1 to dictate the location of each color.
      '''
      bit_rgb = np.linspace(0,1,256)
      if position == None:
          position = np.linspace(0,1,len(colors))
      else:
          if len(position) != len(colors):
              sys.exit("position length must be the same as colors")
          elif position[0] != 0 or position[-1] != 1:
              sys.exit("position must start with 0 and end with 1")
      palette = [(i, (float(r), float(g), float(b), float(a))) for
      i, (r, g, b, a) in enumerate(colors)]
      cmap = Colormap(*palette)
      return cmap