Python str list to list

eg1：

My csv data like this below,i wt count  list nums
2018上,"['C', 'B', 'B', 'B', 'D', 'A', 'B', 'C', 'A', 'D', 'B', 'D', 'A', 'A', 'A', 'C', 'D', 'B', 'C', 'B', 'A', 'C', 'A', 'D', 'A', 'D', 'B', 'D', 'B', 'C', 'B', 'A', 'D', 'B', 'C', 'B、C', 'B', 'B', 'B', 'D', 'B', 'C', 'C', 'B', 'B', 'D', 'A', 'D', 'D', 'C', 'B', 'B', 'A', 'B', 'C', 'B', 'B', 'B', 'A', 'A', 'A', 'C', 'A', 'B', 'A', 'A、A', 'B、C', 'C', 'D', 'B', 'C', 'C', 'A']"


eg:

df_data = np.array(pd.read_csv(answer_file, header=None))
    new_data = []
    for d in df_data:
        y = d[0]
        ya = d[1]      #  '[\'C\',\'A\']'
      #(1)check one
        y2 = np.array(ya) # ['C','A']   #this is what i not want 
        y2_test = y2.shape     # 0-d
　　     y2_test2 = y2.tolist()  # dtype shows not list 

      #the right methon

　　  #(2)check one

　　　 ls = ya.strip('][').split(',')  # dtype show list 
    #（3） right methon
      import ast
    ls = ast.iteral_eval(ya)
    ls = [i.strip() for i in ls]