def get_hash_type(hash_file):
    """
       Checks the type of the given hash. Returns 'md5', 'sha1', 'sha256' or 'Unknown'.

       :type hash_file: ``str``
       :param hash_file: The hash to be checked (required)

       :return: The hash type
       :rtype: ``str``
    """
    hash_len = len(hash_file)
    if (hash_len == 32):
        return 'md5'
    elif (hash_len == 40):
        return 'sha1'
    elif (hash_len == 64):
        return 'sha256'
    else:
        return 'Unknown'