gistfile1.py

def is_a_cat(animal_name):
    if animal_name == 'cat':
        return True
    else:
        return False


def lycanthropize(animal_name):
    return "were-" + animal_name


animals = ['cat', 'dog', 'bird']

# filter a sequence
filtered = list(filter(is_a_cat, animals))
print(filtered)    # ['cat']

# map a sequence
werebeasts = list(map(lycanthropize, animals))
print(werebeasts)  # ['were-cat', 'were-dog', 'were-bird']

# pipeline
werecats = list(map(lycanthropize, filter(is_a_cat, animals)))
print(werecats)    # ['were-cat']