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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 _shutdown(self):
 """Private method. Reset to non-piped spawn"""

        global sconf_global, _ac_config_hs

        if not self.active:
            raise SCons.Errors.UserError("Finish may be called only once!")
        if self.logstream is not None and not dryrun:
            self.logstream.write("\n")
            self.logstream.close()
            self.logstream = None
        # remove the SConfSourceBuilder from the environment
        blds = self.env['BUILDERS']
        del blds['SConfSourceBuilder']
        self.env.Replace( BUILDERS=blds )
        self.active = 0
        sconf_global = None
        if not self.config_h is None:
            _ac_config_hs[self.config_h] = self.config_h_text
        self.env.fs = self.lastEnvFs