1def swallow(name = None, airspeed = None, coconuts = None):
2    """
3    >>> swallow(name = "Brian")
4    This swallow is called Brian
5    >>> swallow(airspeed = 42)
6    This swallow is flying at 42 furlongs per fortnight
7    >>> swallow(coconuts = 3)
8    This swallow is carrying 3 coconuts
9    """
10    if name is not None:
11        print u"This swallow is called", name
12    if airspeed is not None:
13        print u"This swallow is flying at", airspeed, u"furlongs per fortnight"
14    if coconuts is not None:
15        print u"This swallow is carrying", coconuts, u"coconuts"
16