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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_rev(self, fpath):
 """ Get an SCM version number. Try svn and git. """

        rev = None
        
        try:
            cmd = ["git", "log", "-n1", "--pretty=format:\"%h\"", fpath]
            rev = Popen(cmd, stdout=PIPE, stderr=PIPE).communicate()[0]
        except:
            pass
        
        if not rev:
            try:
                cmd = ["svn", "info", fpath]
                svninfo = Popen(cmd,
                                stdout=PIPE,
                                stderr=PIPE).stdout.readlines()
                for info in svninfo:
                    tokens = info.split(":")
                    if tokens[0].strip() == "Last Changed Rev":
                        rev = tokens[1].strip()
            except:
                pass
        
        return rev