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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 _parse_tcl_list(self, attr, list_str):
        '''Turns a string representation of a TCL list into a Python list.

        :param attr: string name of attribute
        :param list_str: string representation of a list
        :returns: Python list
        '''

        list_str = list_str.strip()

        if not list_str:
            return []

        if list_str[0] != '{' and list_str[-1] != '}':
            if list_str.find('none') >= 0:
                return list_str

        if not re.search(self.tcl_list_patterns[attr], list_str):
            raise MalformedTCLListException(
                'TCL list for "%s" is malformed. ' % attr
            )

        list_str = list_str.strip('{').strip('}')
        list_str = list_str.strip()
        return list_str.split()