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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 run(self):
 """ Perform the actual VASP run. Returns: (subprocess.Popen) Used for monitoring. """

        cmd = list(self.vasp_cmd)
        if self.auto_gamma:
            vi = VaspInput.from_directory(".")
            kpts = vi["KPOINTS"]
            if kpts.style == Kpoints.supported_modes.Gamma \
                    and tuple(kpts.kpts[0]) == (1, 1, 1):
                if self.gamma_vasp_cmd is not None and which(
                        self.gamma_vasp_cmd[-1]):
                    cmd = self.gamma_vasp_cmd
                elif which(cmd[-1] + ".gamma"):
                    cmd[-1] += ".gamma"
        logger.info("Running {}".format(" ".join(cmd)))
        with open(self.output_file, 'w') as f_std, \
                open(self.stderr_file, "w", buffering=1) as f_err:
            # use line buffering for stderr
            p = subprocess.Popen(cmd, stdout=f_std, stderr=f_err)
        return p