try:
    import xml.etree.cElementTree as ET
except ImportError:
    import xml.etree.ElementTree as ET

KNOWN_FIELD_TAGS = ['100', '110', '151']


class INLXmlParser:
    def __init__(self, reader, whitelist=None):
        self.reader = reader
        self.whitelist = whitelist or KNOWN_FIELD_TAGS

    def clearxml(self):
        newTreeRoot = ET.Element('data')

        # # scan the datafields in the records and copy to the new one only the tags in the whitelist
        # for record in root:    # create new record
        newRecord = ET.SubElement(newTreeRoot, 'record')
        for field in self.reader:
            fieldtag = field.attrib.get('tag')
            if fieldtag in self.whitelist:
                newFieldTag = fieldtag
                # tag 700 and 400 are the same
                if newFieldTag == '700':
                    newFieldTag = '400'
                newTag = ET.SubElement(newRecord, 'datafield', {'tag': newFieldTag})
                for data in field:
                    subData = ET.SubElement(newTag, data.tag, data.attrib)
                    subData.text = data.text

        newTree = ET.ElementTree(newTreeRoot)
        return newTree