code: def __dump(df,relation='data',description=''):
      
      attrs = []
      for col in df.columns:
          attr = col.split('@')
          if attr[1].count('{')>0 and attr[1].count('}')>0:
              vals = attr[1].replace('{','').replace('}','').split(',')
              attrs.append((attr[0],vals))
          else:
              attrs.append((attr[0],attr[1]))
  
      data = list(df.values)
      result = {
          'attributes':attrs,
          'data':data,
          'description':description,
          'relation':relation
      }
      return result
docs: dump DataFrame to liac-arff
      :param DataFrame df: 
      :param str relation: 
      :param str description: 
      :rtype: dict
      :return: liac-arff dict