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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 show_abierrors(self, nids=None, stream=sys.stdout):
 """ Write to the given stream the list of ABINIT errors for all tasks whose status is S_ABICRITICAL. Args: nids: optional list of node identifiers used to filter the tasks. stream: File-like object. Default: sys.stdout """

        lines = []
        app = lines.append

        for task in self.iflat_tasks(status=self.S_ABICRITICAL, nids=nids):
            header = "=== " + task.qout_file.path + "==="
            app(header)
            report = task.get_event_report()

            if report is not None:
                app("num_errors: %s, num_warnings: %s, num_comments: %s" % (
                    report.num_errors, report.num_warnings, report.num_comments))
                app("*** ERRORS ***")
                app("\n".join(str(e) for e in report.errors))
                app("*** BUGS ***")
                app("\n".join(str(b) for b in report.bugs))

            else:
                app("get_envent_report returned None!")

            app("=" * len(header) + 2*"\n")

        return stream.writelines(lines)