def get_version(self, paths=None, default="unknown"):
        """Get version number of installed module, 'None', or 'default'

        Search 'paths' for module.  If not found, return 'None'.  If found,
        return the extracted version attribute, or 'default' if no version
        attribute was specified, or the value cannot be determined without
        importing the module.  The version is formatted according to the
        requirement's version format (if any), unless it is 'None' or the
        supplied 'default'.
        """

        if self.attribute is None:
            try:
                f, p, i = find_module(self.module, paths)
                if f:
                    f.close()
                return default
            except ImportError:
                return None

        v = get_module_constant(self.module, self.attribute, default, paths)

        if v is not None and v is not default and self.format is not None:
            return self.format(v)

        return v
Get version number of installed module, 'None', or 'default'

        Search 'paths' for module.  If not found, return 'None'.  If found,
        return the extracted version attribute, or 'default' if no version
        attribute was specified, or the value cannot be determined without
        importing the module.  The version is formatted according to the
        requirement's version format (if any), unless it is 'None' or the
        supplied 'default'.
        
product/gradle-plugin/src/main/python/setuptools/depends.py