class DocProcess(object):

 @classmethod
 def strip_html(cls, text):
  """
   Delete html tags in text.
   text is String
  """
  new_text = " "
  is_html = False
  for character in text:
   if character == "<":
    is_html = True
   elif character == ">":
    is_html = False
    new_text += " "
   elif is_html is False:
    new_text += character
  return new_text

 @classmethod
 def separate_words(cls, text, min_lenth=3):
  """
   Separate text into words in list.
  """
  splitter = re.compile("\\W+")
  return [s.lower() for s in splitter.split(text) if len(s) > min_lenth]

 @classmethod
 def get_words_frequency(cls, words_list):
  """
   Get frequency of words in words_list.
   return a dict.
  """
  num_words = {}
  for word in words_list:
   num_words[word] = num_words.get(word, 0) + 1
  return num_words