code: def fetch_sdss_corrected_spectra(
      data_home=None, download_if_missing=True
  ):
      """Loader for Iterative PCA pre-processed galaxy spectra
  
      Parameters
      ----------
      data_home : optional, default=None
          Specify another download and cache folder for the datasets. By default
          all astroML data is stored in '~/astroML_data'.
  
      download_if_missing : optional, default=True
          If False, raise a IOError if the data is not locally available
          instead of trying to download the data from the source site.
  
      Returns
      -------
      data : NpzFile
          The data dictionary
  
      Notes
      -----
      This is the file created by the example script
      examples/datasets/compute_sdss_pca.py
      """
      data_home = get_data_home(data_home)
  
      data_file = os.path.join(data_home, os.path.basename(DATA_URL))
  
      if not os.path.exists(data_file):
          if not download_if_missing:
              raise IOError(
                  "data not present on disk. "
                  "set download_if_missing=True to download"
              )
  
          print(
              "downloading PCA-processed SDSS spectra from %s to %s"
              % (DATA_URL, data_home)
          )
  
          databuffer = download_with_progress_bar(DATA_URL)
          open(data_file, "wb").write(databuffer)
  
      data = np.load(data_file)
  
      return data
  
imports: import os
  import numpy
  from .None import get_data_home
  from .tools import download_with_progress_bar
label_desc: Use image node_id 3 for calling a global function with example usage: fetch_sdss_corrected_spectra(data_home, download_if_missing) and returns: data