<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def read(self, file_or_filename):
 """ Parses a PSAT data file and returns a case object file_or_filename: File object or path to PSAT data file return: Case object """

        self.file_or_filename = file_or_filename

        logger.info("Parsing PSAT case file [%s]." % file_or_filename)

        t0 = time.time()

        self.case = Case()

        # Name the case
        if isinstance(file_or_filename, basestring):
            name, _ = splitext(basename(file_or_filename))
        else:
            name, _ = splitext(file_or_filename.name)

        self.case.name = name

        bus_array = self._get_bus_array_construct()
        line_array = self._get_line_array_construct()
        # TODO: Lines.con - Alternative line data format
        slack_array = self._get_slack_array_construct()
        pv_array = self._get_pv_array_construct()
        pq_array = self._get_pq_array_construct()
        demand_array = self._get_demand_array_construct()
        supply_array = self._get_supply_array_construct()
        # TODO: Varname.bus (Bus names)

        # Pyparsing case:
        case = \
            ZeroOrMore(matlab_comment) + bus_array + \
            ZeroOrMore(matlab_comment) + line_array + \
            ZeroOrMore(matlab_comment) + slack_array + \
            ZeroOrMore(matlab_comment) + pv_array + \
            ZeroOrMore(matlab_comment) + pq_array + \
            ZeroOrMore(matlab_comment) + demand_array + \
            ZeroOrMore(matlab_comment) + supply_array

        case.parseFile(file_or_filename)

        elapsed = time.time() - t0
        logger.info("PSAT case file parsed in %.3fs." % elapsed)

        return self.case