code: def parse_sgm(
      path_or_buffer: Union[str, IO[AnyStr]],
      out_path_or_buffer: Optional[Union[str, IO[AnyStr]]] = None,
      return_sentences=False,
      clean_space=True,
  ) -> Optional[List[str]]:
      """Returns sentences from a single SGML file. This is compatible to the behavior of
      `input-from-sgm.perl` in
      https://github.com/moses-smt/mosesdecoder/blob/a89691fee395bb7eb6dfd51e368825f0578f437d/scripts/ems/support/input-from-sgm.perl
  
      Parameters
      ----------
      path_or_buffer
          The source path to parse the file
      out_path_or_buffer
          The output path
      return_sentences
          Whether to return the parsed sentences
      clean_space
          Whether to clean the spaces in the sentence with the similar strategy in
           input-from-sgm.perl.
  
      Returns
      -------
      sentences
          The list contains the parsed sentences in the input file.
          If the return_sentences is False, return None.
      """
      if out_path_or_buffer is None:
          assert (
              return_sentences
          ), "Must return sentences if the output path is not specified!"
      if return_sentences:
          sentences = []
      else:
          sentences = None
      f_buffer = _get_buffer(path_or_buffer, "r")
      of_buffer = _get_buffer(out_path_or_buffer, "w")
      seg_re = re.compile(r"<seg.*?>(.*)</seg>.*?")
      for line in f_buffer:
          if isinstance(line, bytes):
              line = line.decode("utf-8")
          seg_match = re.match(seg_re, line)
          if seg_match:
              assert (
                  len(seg_match.groups()) == 1
              ), "File content is not supported, unmatched line: {}".format(
                  line
              )
              line = seg_match.groups()[0]
              if clean_space:
                  line = _clean_space(line)
              if of_buffer is not None:
                  of_buffer.write(line + "\n")
              if sentences is not None:
                  sentences.append(line)
      if of_buffer is not None:
          of_buffer.close()
      return sentences
  
imports: from typing import List, Union, IO, AnyStr, Tuple, Optional
  import re
  import os
  import argparse
  import zipfile
  import shutil
  import functools
  import tarfile
  import gzip
  import json
  from xml.etree import ElementTree
  from gluonnlp.data.filtering import ProfanityFilter
  from gluonnlp.utils.misc import file_line_number, download, load_checksum_stats
  from gluonnlp.base import get_data_home_dir, get_repo_url
label_desc: Use image node_id 4 for calling a global function with example usage: parse_sgm(path_or_buffer, out_path_or_buffer, return_sentences, clean_space) and returns: sentences