old_contents: import sys
  from datetime import datetime
  from difflib import unified_diff
  from pathlib import Path
  from typing import Optional
  
  
  def format_simplified(import_line: str) -> str:
      import_line = import_line.strip()
      if import_line.startswith("from "):
          import_line = import_line.replace("from ", "")
          import_line = import_line.replace(" import ", ".")
      elif import_line.startswith("import "):
          import_line = import_line.replace("import ", "")
  
      return import_line
  
  
  def format_natural(import_line: str) -> str:
      import_line = import_line.strip()
      if not import_line.startswith("from ") and not import_line.startswith("import "):
          if "." not in import_line:
              return "import {0}".format(import_line)
          parts = import_line.split(".")
          end = parts.pop(-1)
          return "from {0} import {1}".format(".".join(parts), end)
  
      return import_line
  
  
  def show_unified_diff(*, file_input: str, file_output: str, file_path: Optional[Path]) -> None:
      file_name = '' if file_path is None else str(file_path)
      file_mtime = str(datetime.now() if file_path is None
                       else datetime.fromtimestamp(file_path.stat().st_mtime))
  
      unified_diff_lines = unified_diff(
          file_input.splitlines(keepends=True),
          file_output.splitlines(keepends=True),
          fromfile=file_name + ':before',
          tofile=file_name + ':after',
          fromfiledate=file_mtime,
          tofiledate=str(datetime.now())
      )
      for line in unified_diff_lines:
          sys.stdout.write(line)
  
  
  def ask_whether_to_apply_changes_to_file(fpath: str) -> bool:
      answer = None
      while answer not in ('yes', 'y', 'no', 'n', 'quit', 'q'):
          answer = input("Apply suggested changes to '{0}' [y/n/q]? ".format(fpath)).lower()
          if answer in ('no', 'n'):
              return False
          if answer in ('quit', 'q'):
              sys.exit(1)
      return True
  
new_contents: import sys
  from datetime import datetime
  from difflib import unified_diff
  from pathlib import Path
  from typing import Optional
  
  
  def format_simplified(import_line: str) -> str:
      import_line = import_line.strip()
      if import_line.startswith("from "):
          import_line = import_line.replace("from ", "")
          import_line = import_line.replace(" import ", ".")
      elif import_line.startswith("import "):
          import_line = import_line.replace("import ", "")
  
      return import_line
  
  
  def format_natural(import_line: str) -> str:
      import_line = import_line.strip()
      if not import_line.startswith("from ") and not import_line.startswith("import "):
          if "." not in import_line:
              return "import {0}".format(import_line)
          parts = import_line.split(".")
          end = parts.pop(-1)
          return "from {0} import {1}".format(".".join(parts), end)
  
      return import_line
  
  
  def show_unified_diff(*, file_input: str, file_output: str, file_path: Optional[Path]) -> None:
      file_name = '' if file_path is None else str(file_path)
      file_mtime = str(datetime.now() if file_path is None
                       else datetime.fromtimestamp(file_path.stat().st_mtime))
  
      unified_diff_lines = unified_diff(
          file_input.splitlines(keepends=True),
          file_output.splitlines(keepends=True),
          fromfile=file_name + ':before',
          tofile=file_name + ':after',
          fromfiledate=file_mtime,
          tofiledate=str(datetime.now())
      )
      for line in unified_diff_lines:
          sys.stdout.write(line)
  
  
  def ask_whether_to_apply_changes_to_file(file_path: str) -> bool:
      answer = None
      while answer not in ('yes', 'y', 'no', 'n', 'quit', 'q'):
          answer = input("Apply suggested changes to '{0}' [y/n/q]? ".format(file_path)).lower()
          if answer in ('no', 'n'):
              return False
          if answer in ('quit', 'q'):
              sys.exit(1)
      return True
  
subject: Update format.py