code: def download_meka(version=None):
      """Downloads a given version of the MEKA library and returns its classpath
  
      Parameters
      ----------
      version : str
          the MEKA version to download, default falls back to currently supported version 1.9.2
  
      Returns
      -------
      string
          meka class path string for installed version
  
      Raises
      ------
      IOError
          if unpacking the meka release file does not provide a proper setup
      Exception
          if MD5 mismatch happens after a download error
      """
      version = version or SUPPORTED_VERSION
      meka_release_string = "meka-release-{}".format(version)
      file_name = meka_release_string + "-bin.zip"
      meka_path = get_data_home(subdirectory="meka")
      target_path = os.path.join(meka_path, file_name)
      path_to_lib = os.path.join(meka_path, meka_release_string, "lib")
  
      if os.path.exists(target_path):
          print("MEKA {} found, not downloading".format(version))
  
      else:
          print("MEKA {} not found, downloading".format(version))
          release_url = "http://downloads.sourceforge.net/project/meka/meka-{}/".format(
              version
          )
          _download_single_file(file_name, target_path, release_url)
  
          found_md5 = _get_md5(target_path)
          if SUPPORTED_VERSION_MD5 != found_md5:
              raise Exception(
                  "MD5 mismatch - possible MEKA download error"
              )
  
      if not os.path.exists(path_to_lib):
          with zipfile.ZipFile(target_path, "r") as meka_zip:
              print(
                  "Unzipping MEKA {} to {}".format(
                      version, meka_path + os.path.sep
                  )
              )
              meka_zip.extractall(path=meka_path + os.path.sep)
  
      if not os.path.exists(
          os.path.join(path_to_lib, "meka-{}.jar".format(version))
      ):
          raise IOError(
              "Something went wrong, MEKA files missing, please file a bug report"
          )
  
      return path_to_lib + os.path.sep
  
imports: import os
  import shlex
  import subprocess
  import sys
  import tempfile
  import zipfile
  from builtins import filter
  from builtins import map
  from builtins import range
  from builtins import str
  import scipy.sparse
  from ..base import MLClassifierBase
  from ..dataset import save_to_arff, get_data_home, _download_single_file, _get_md5
label_desc: Use image node_id 1 for calling a global function with example usage: download_meka(version) and returns: unknown