import xml.etree.ElementTree as ET
import csv
tree = ET.parse('data.xml')
root = tree.getroot()

with open('data.csv', 'wb') as csvfile:
    spamwriter = csv.writer(csvfile)
    for neighbor in root.iter('DATI'):
        parent = neighbor.attrib.get("ISTANTE")
        parent = parent[:-4]
        vm = neighbor[0].text
        vmin = neighbor[1].text
        vmax = neighbor[1].text
        spamwriter.writerow([parent, vm, vmin, vmax])