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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def blast_pdb(self, seq_ident_cutoff=0, evalue=0.0001, display_link=False, outdir=None, force_rerun=False):
 """BLAST this sequence to the PDB"""

        if not outdir:
            outdir = self.sequence_dir
            if not outdir:
                raise ValueError('Output directory must be specified')

        if not self.seq_str:
            log.error('{}: no sequence loaded'.format(self.id))
            return None

        try:
            blast_results = ssbio.databases.pdb_seq.blast_pdb(self.seq_str,
                                                              outfile='{}_blast_pdb.xml'.format(custom_slugify(self.id)),
                                                              outdir=outdir,
                                                              force_rerun=force_rerun,
                                                              evalue=evalue,
                                                              seq_ident_cutoff=seq_ident_cutoff,
                                                              link=display_link)
        except requests.ConnectionError as e:
            log.error('{}: BLAST request timed out'.format(self.id))
            print(e)
            return None

        return blast_results