code: def dtype_to_char(dtype):
      """Return character that represents data type."""
      dtype_char = {
          "complex64": "c",
          "complex128": "z",
          "float32": "f",
          "float64": "d",
          "int8": "b",
          "int16": "w",
          "int32": "i",
          "int64": "l",
      }
      if dtype in dtype_char:
          return dtype_char[dtype]
      else:
          return "X"
  
imports: import os
  from functools import reduce
  import numpy
  import pytensor
  from pytensor.compile import Function, builders
  from pytensor.graph.basic import Apply, Constant, Variable, graph_inputs
  from pytensor.graph.fg import FunctionGraph
  from pytensor.printing import pydot_imported, pydot_imported_msg
label_desc: Use image node_id 6 for calling a global function with example usage: dtype_to_char(dtype) and returns: dtype_char, str