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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 __setuptools_version(self):

 """Read setuptools version from the underlying ez_setup script."""

        # Read the script directly as a file instead of importing it as a
        # Python module and reading the value from the loaded module's global
        # DEFAULT_VERSION variable. Not all ez_setup scripts are compatible
        # with all Python environments and so importing them would require
        # doing so using a separate process run in the target Python
        # environment instead of the current one.
        f = open(self.script_path(), "r")
        try:
            matcher = re.compile(r'\s*DEFAULT_VERSION\s*=\s*"([^"]*)"\s*$')
            for i, line in enumerate(f):
                if i > 50:
                    break
                match = matcher.match(line)
                if match:
                    return match.group(1)
        finally:
            f.close()
        self.__error("error parsing setuptools installation script '%s'" % (
            self.script_path(),))