code: def get_bibliography(lsst_bib_names=None, bibtex=None):
      
      bibtex_data = get_lsst_bibtex(bibtex_filenames=lsst_bib_names)
  
      # Parse with pybtex into BibliographyData instances
      pybtex_data = [pybtex.database.parse_string(_bibtex, 'bibtex')
                     for _bibtex in bibtex_data.values()]
  
      # Also parse local bibtex content
      if bibtex is not None:
          pybtex_data.append(pybtex.database.parse_string(bibtex, 'bibtex'))
  
      # Merge BibliographyData
      bib = pybtex_data[0]
      if len(pybtex_data) > 1:
          for other_bib in pybtex_data[1:]:
              for key, entry in other_bib.entries.items():
                  bib.add_entry(key, entry)
  
      return bib
docs: Make a pybtex BibliographyData instance from standard lsst-texmf
      bibliography files and user-supplied bibtex content.
  
      Parameters
      ----------
      lsst_bib_names : sequence of `str`, optional
          Names of lsst-texmf BibTeX files to include. For example:
  
          .. code-block:: python
  
             ['lsst', 'lsst-dm', 'refs', 'books', 'refs_ads']
  
          Default is `None`, which includes all lsst-texmf bibtex files.
  
      bibtex : `str`
          BibTeX source content not included in lsst-texmf. This can be content
          from a import ``local.bib`` file.
  
      Returns
      -------
      bibliography : `pybtex.database.BibliographyData`
          A pybtex bibliography database that includes all given sources:
          lsst-texmf bibliographies and ``bibtex``.