def to(items, output=None):
strings = (format_collection(item) for item in items)<EOL>if output is None:<EOL><INDENT>return strings<EOL><DEDENT>else:<EOL><INDENT>for s in strings:<EOL><INDENT>output.write(s + '<STR_LIT:\n>')<EOL><DEDENT><DEDENT>
Present a collection of items as TSV

    The items in the collection can themselves be any iterable collection.
    (Single field structures should be represented as one tuples.)

    With no output parameter, a generator of strings is returned. If an output
    parameter is passed, it should be a file-like object. Output is always
    newline separated.