A simple CML parser written in Python

Python is a powerful programming language. It can be easily extended by importing modules.
Below is a simple module for parsing CML file. As you can see, it's really easy to add the support for another tags.

import xml.sax.handler

class CMLHandler(xml.sax.handler.ContentHandler):
  def __init__(self):
      self.id = ""
      self.formula = ""
      self.inIdentifier = False
      self.inchi = "InChI/1="
      self.inInChI = False
      self.inBasic = False
      self.name = ""
      self.inName = False
      self.weight = ""
      self.inWeight = False
      self.mpt = ""
      self.mptSet = False
      self.inMpt = False
      self.bpt = ""
      self.inBpt = False
      self.bptSet = False

  def startElement(self, name, attributes):
      if name == "molecule":
          self.id = attributes["id"]

      if name == "formula":
          self.formula = attributes["concise"]

      if name == "identifier":
          self.inIdentifier = True
          if attributes.has_key("version") and attributes["version"] == "InChI/1":
              self.inInChI = True

      if name == "basic":
          self.inBasic = True

      if name == "name":
          self.inName = True

      if name == "scalar":
          if attributes["dictRef"] == "cml:molwt":
              self.inWeight = True
          elif attributes["dictRef"] == "cml:mpt":
              self.inMpt = True
          elif attributes["dictRef"] == "cml:bpt":
              self.inBpt = True

  def characters(self, data):
      if self.inName:
          self.name += data

      if self.inWeight:
          self.weight += data

      if self.inMpt:
          self.mpt += data

      if self.inBpt:
          self.bpt += data

      if self.inBasic and self.inInChI:
          self.inchi += data

  def endElement(self,name):
      if name == "identifier":
          self.inIdenfitier = False

      if name == "basic":
          self.inBasic = False
          if self.inInChI:
            self.inInChI = False

      if name == "name":
          self.inName = False

      if name == "inchi":
          self.inInChI = False

      if name == "scalar":
          if self.inWeight:
              self.inWeight = False
          elif self.inMpt:
              self.inMpt = False
              self.mptSet = True
          elif self.inBpt:
              self.inBpt = False
              self.bptSet = True