<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _create_path(self,xpath):
 """ Started to write an xpath parser to create the specified path but there are many ways to specify a path in xpath - it is too expressive. This is not a sensible thing to do from inside a property function. Let it return an error unless the path exists and add helper functions to create the specific metadata block that is required. """

        raise NotImplementedError()

        split_path = xpath.split('/')
        test_paths = ['/'.join(sp[:i+1]) for i in range(1, len(split_path))]

        for path in reversed(test_paths):
            result = self._eval_xpath(path)
            result_length = len(result)
            if  result_length == 0:
                # Still no elements found
                continue
            elif result_length == 1:
                result = result[0]
                break
            else:
                raise XmlDogmaException('Invalid xpath expression "%s" returns more than one element!' % xpath)

        else:
            raise XmlDogmaException('Root element "%s" of xpath expression "%s" not found while trying to create path.' % (path, xpath))

        existing_elemet = result
        existing_path = path
        existing_index = test_paths.index(existing_path)

        for new_element in split_path[existing_index+1:]:

            #Regex it!
            # 'employee[secretary][assistant]' => ['employee', 'secretary', 'assistant', '']
            # 'toy[attribute::color = "red"]' => ['toy', 'attribute::color = "red"', '']
            parts = re.split('\[(.*?)\]',new_element)
            #@TODO - find a better regex that does not include one empty string for each bracket
            try:
                while True:
                    parts.remove('')
            except ValueError:
                pass

            tag = parts[0]
            predicates = parts[1:]

            e = etree.Element(tag)


            ### Did not finish implementing... see comment above about why its a bad idea
            for predicate in predicates:
                if predicate.isdigit():
                    # it is specifying where to insert this child
                    pass
                elif predicate.startswith('@'):
                    #parse the attribute and set it...
                    pass
                else:
                    pass