def get_key_of_min(dict_obj):
    """Returns the key that maps to the minimal value in the given dict.

    Example:
    --------
    >>> dict_obj = {'a':2, 'b':1}
    >>> print(get_key_of_min(dict_obj))
    b
    """
    return min(dict_obj, key=lambda key: dict_obj[key])
