code: def unflatten(
      source, stagger=None, fanout=False, chain=None, encoding=ENCODING
  ):
      """Return DOT ``source`` piped through Graphviz *unflatten* preprocessor.
  
      Args:
          source (str): The DOT source to process (improve layout aspect ratio).
          stagger (int): Stagger the minimum length of leaf edges between 1 and this small integer.
          fanout (bool): Fanout nodes with indegree = outdegree = 1 when staggering (requires ``stagger``).
          chain (int): Form disconnected nodes into chains of up to this many nodes.
          encoding: Encoding used to encode unflatten stdin and decode its stdout.
  
      Returns:
          str: Decoded stdout of the Graphviz unflatten command.
  
      Raises:
          graphviz.RequiredArgumentError: If ``fanout`` is given but ``stagger`` is None.
          graphviz.ExecutableNotFound: If the Graphviz unflatten executable is not found.
          subprocess.CalledProcessError: If the exit status is non-zero.
  
      See also:
          https://www.graphviz.org/pdf/unflatten.1.pdf
      """
      if fanout and stagger is None:
          raise RequiredArgumentError("fanout given without stagger")
  
      cmd = ["unflatten"]
      if stagger is not None:
          cmd += ["-l", str(stagger)]
      if fanout:
          cmd.append("-f")
      if chain is not None:
          cmd += ["-c", str(chain)]
  
      out, _ = run(
          cmd, input=source, capture_output=True, encoding=encoding
      )
      return out
  
imports: import errno
  import logging
  import os
  import platform
  import re
  import subprocess
  from .None import _compat
  from .None import tools
label_desc: Use image node_id 5 for calling a global function with example usage: unflatten(source, stagger, fanout, chain, encoding) and returns: out