text: Title: Error in training custom YML file as corpus
  Body: Code:
  `english_bot = ChatBot("Chatterbot",
                        storage_adapter="chatterbot.storage.SQLStorageAdapter",
                               )
  
  trainer = ChatterBotCorpusTrainer(english_bot)
  trainer.train("data/train11.yml")
  `
  YML File:
  - - Can you tell me the history of the college?
    - HITAM today is a standing testimony to the vision of Arutla Prashanth, its Founder & Chairman.It was established in 2001.
    - what is the history of the college?
  - - Hi
    - hello how are you?
    - Hey there
    - whatsup?
    - sup
  - - how are you?
    - I am great
    - I am fine
    - Fine how are you?
  
  After running this I am getting the error as
  Traceback (most recent call last):
  
    File "app.py", line 38, in <module>
      trainer.train("data/train11.yml")
    File "C:\ProgramData\Anaconda3\lib\site-packages\chatterbot\trainers.py", line 138, in train
      for corpus, categories, file_path in load_corpus(*data_file_paths):
    File "C:\ProgramData\Anaconda3\lib\site-packages\chatterbot\corpus.py", line 65, in load_corpus
      conversations = corpus_data.get('conversations', [])
  AttributeError: 'list' object has no attribute 'get'
  
  I am using  Python 3.7.0 and Chatterbot version 1.0.4
  Hey @gunthercox can you please help me out