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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 _get_file_version(self, infile):
 """Returns infile version string."""


        # Determine file version
        for line1 in infile:
            if line1.strip() != "[Pyspread save file version]":
                raise ValueError(_("File format unsupported."))
            break

        for line2 in infile:
            return line2.strip()