Author is passed as dictionary with parsed and raw data. This function adds
    *experimental support* for transport of all author fields based on RAW
    data, instead of parsed fields.

    If this proves as wrong, the code will be switched to use of parsed data
    again.

    Example of the input `author_data`::

       "author":{
          "name":"Grada Publishing",
          "code":"kn20080316009",
          "linked_forms":[
             "Grada Publishing a.s.",
             "Grada (nakladatelství)",
             "Nakladatelství Grada"
          ],
          "is_corporation":true,
          "record":{
             "7":[
                "kn20080316009"
             ],
             "i1":"2",
             "i2":" ",
             "a":[
                "Grada Publishing"
             ]
          },
          "alt_name":"Grada Publishing [organizace] (Grada Publishing a.s.,
                      Grada (nakladatelství), Nakladatelství Grada)"
        }

    This is transformed into::

        1102  L $$aGrada Publishing$$b $$7kn20080316009

    Fields used in the output are taken from the ``is_corporation``,
    ``record`` fields (``i1``, ``i2``, ``7`` and ``a``).

    Returns:
        str: String containing the line which will be included to the MRC.

def serialize_author(author_data):
    """
    Author is passed as dictionary with parsed and raw data. This function adds
    *experimental support* for transport of all author fields based on RAW
    data, instead of parsed fields.

    If this proves as wrong, the code will be switched to use of parsed data
    again.

    Example of the input `author_data`::

       "author":{
          "name":"Grada Publishing",
          "code":"kn20080316009",
          "linked_forms":[
             "Grada Publishing a.s.",
             "Grada (nakladatelství)",
             "Nakladatelství Grada"
          ],
          "is_corporation":true,
          "record":{
             "7":[
                "kn20080316009"
             ],
             "i1":"2",
             "i2":" ",
             "a":[
                "Grada Publishing"
             ]
          },
          "alt_name":"Grada Publishing [organizace] (Grada Publishing a.s.,
                      Grada (nakladatelství), Nakladatelství Grada)"
        }

    This is transformed into::

        1102  L $$aGrada Publishing$$b $$7kn20080316009

    Fields used in the output are taken from the ``is_corporation``,
    ``record`` fields (``i1``, ``i2``, ``7`` and ``a``).

    Returns:
        str: String containing the line which will be included to the MRC.
    """
    record = author_data["record"]
    i1 = record["i1"]
    i2 = record["i2"]

    # make sure that all required fields will be created
    if "a" not in record:
        record["a"] = " "

    if author_data["is_corporation"]:
        code = "110"
        if "b" not in record:
            record["b"] = " "
    else:
        code = "100"
        if "d" not in record:
            record["d"] = " "
        if "4" not in record:
            record["4"] = " "

    out = "%s%s%s L " % (code, i1, i2)
    for key in resorted(key for key in record if len(key) == 1):
        for item in record[key]:
            out += "$$%s%s" % (key, item)

    return out