code: def git_content(git_file):
      """
      This function will extract a file from a git repository, one located on
      the filesystem.
      The expected format is git+file:///path/to/your/repo/path_to_file@version
  
      Args:
        env_file (str): consist of path to repo, @, version, and file information
                        Ex: git+file:///home/smeds/snakemake-wrappers/bio/fastqc/wrapper.py@0.19.3
      Returns:
          file content or None if the expected format isn't meet
      """
      import git
  
      if git_file.startswith("git+file:"):
          (root_path, file_path, version) = split_git_path(git_file)
          return git.Repo(root_path).git.show(f"{version}:{file_path}")
      else:
          raise WorkflowError(
              "Provided git path ({}) doesn't meet the "
              "expected format:".format(git_file)
              + ", expected format is "
              "git+file://PATH_TO_REPO/PATH_TO_FILE_INSIDE_REPO@VERSION"
          )
  
imports: import os
  import re
  from snakemake.exceptions import WorkflowError
label_desc: Use image node_id 4 for calling a global function with example usage: git_content(git_file) and returns: git