class_docstr: Provide getitem syntax for functions
  
  >>> def inc(x):
  ...     return x + 1
  
  >>> I = IndexCallable(inc)
  >>> I[3]
  4
class_docstr_tok: ["Provide","getitem","syntax","for","functions",">",">",">","def","inc","(","x",")",":","...","return","x","+","1",">",">",">","I","=","IndexCallable","(","inc",")",">",">",">","I","[","3","]","4"]
code: def __init__(self, fn):
      self.fn = fn
  
file_path: datashader/datashader/datashape/internal_utils.py
imports: from __future__ import print_function, division, absolute_import
  import keyword
  import re
label_desc: Use image node_id 1 to create a new IndexCallable object  with example: obj = IndexCallable(fn)