code: def getmode(mode):
      """Gets a mode descriptor for the given mode."""
      global _modes
      if not _modes:
          # initialize mode cache
          modes = {}
          endian = "<" if sys.byteorder == "little" else ">"
          for m, (basemode, basetype, bands, typestr) in {
              # core modes
              # Bits need to be extended to bytes
              "1": ("L", "L", ("1",), "|b1"),
              "L": ("L", "L", ("L",), "|u1"),
              "I": ("L", "I", ("I",), endian + "i4"),
              "F": ("L", "F", ("F",), endian + "f4"),
              "P": ("P", "L", ("P",), "|u1"),
              "RGB": ("RGB", "L", ("R", "G", "B"), "|u1"),
              "RGBX": ("RGB", "L", ("R", "G", "B", "X"), "|u1"),
              "RGBA": ("RGB", "L", ("R", "G", "B", "A"), "|u1"),
              "CMYK": ("RGB", "L", ("C", "M", "Y", "K"), "|u1"),
              "YCbCr": ("RGB", "L", ("Y", "Cb", "Cr"), "|u1"),
              # UNDONE - unsigned |u1i1i1
              "LAB": ("RGB", "L", ("L", "A", "B"), "|u1"),
              "HSV": ("RGB", "L", ("H", "S", "V"), "|u1"),
              # extra experimental modes
              "RGBa": ("RGB", "L", ("R", "G", "B", "a"), "|u1"),
              "BGR;15": ("RGB", "L", ("B", "G", "R"), "|u1"),
              "BGR;16": ("RGB", "L", ("B", "G", "R"), "|u1"),
              "BGR;24": ("RGB", "L", ("B", "G", "R"), "|u1"),
              "LA": ("L", "L", ("L", "A"), "|u1"),
              "La": ("L", "L", ("L", "a"), "|u1"),
              "PA": ("RGB", "L", ("P", "A"), "|u1"),
          }.items():
              modes[m] = ModeDescriptor(
                  m, bands, basemode, basetype, typestr
              )
          # mapping modes
          for i16mode, typestr in {
              # I;16 == I;16L, and I;32 == I;32L
              "I;16": "<u2",
              "I;16S": "<i2",
              "I;16L": "<u2",
              "I;16LS": "<i2",
              "I;16B": ">u2",
              "I;16BS": ">i2",
              "I;16N": endian + "u2",
              "I;16NS": endian + "i2",
              "I;32": "<u4",
              "I;32B": ">u4",
              "I;32L": "<u4",
              "I;32S": "<i4",
              "I;32BS": ">i4",
              "I;32LS": "<i4",
          }.items():
              modes[i16mode] = ModeDescriptor(
                  i16mode, ("I",), "L", "L", typestr
              )
          # set global mode cache atomically
          _modes = modes
      return _modes[mode]
  
imports: import sys
label_desc: Use image node_id 1 for calling a global function with example usage: getmode(mode) and returns: _modes