code: def call(f):
      """
      Wrap a function in a processor that calls `f` on the argument before
      passing it along.
  
      Useful for creating simple arguments to the `@preprocess` decorator.
  
      Parameters
      ----------
      f : function
          Function accepting a single argument and returning a replacement.
  
      Examples
      --------
      >>> @preprocess(x=call(lambda x: x + 1))
      ... def foo(x):
      ...     return x
      ...
      >>> foo(1)
      2
      """
  
      @wraps(f)
      def processor(func, argname, arg):
          return f(arg)
  
      return processor
  
file_path: catalyst/catalyst/utils/preprocess.py
imports: from textwrap import dedent
  from types import CodeType
  from functools import wraps
  from inspect import getargspec
  from uuid import uuid4
  from toolz.curried.operator import getitem
  from six import viewkeys, exec_, PY3
label_desc: Use image node_id 2 for calling a global function with example usage: call(f) and returns: processor, f