code: def _dicts_have_unique_keys(dics):
      
      key_itr = anyconfig.compat.from_iterable(d.keys() for d in dics)
      return len(set(key_itr)) == sum(len(d) for d in dics)
docs: :param dics: [<dict or dict-like object>], must not be [] or [{...}]
      :return: True if all keys of each dict of 'dics' are unique
  
      # Enable the followings if to allow dics is [], [{...}]:
      # >>> all(_dicts_have_unique_keys([d]) for [d]
      # ...     in ({}, {'a': 0}, {'a': 1, 'b': 0}))
      # True
      # >>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2, 'c': 0}])
      # True
  
      >>> _dicts_have_unique_keys([{}, {'a': 1}, {'a': 2}])
      False
      >>> _dicts_have_unique_keys([{}, {'a': 1}, {'b': 2}, {'b': 3, 'c': 0}])
      False
      >>> _dicts_have_unique_keys([{}, {}])
      True