>>> from bigrames import extreu_bigrames

>>> bigrama = {'a': ['cat']}
>>> text = 'a cat jumps and runs fast a dog jumps high'
>>> resultat = extreu_bigrames(text, bigrama)
>>> bigrama == {
...     'a': ['cat', 'dog'],
...     'cat': ['jumps'],
...     'jumps': ['and', 'high'],
...     'and': ['runs'],
...     'runs': ['fast'],
...     'fast': ['a'],
...     'dog': ['jumps']
... }
True
>>> resultat
[('a', ['cat', 'dog']), ('and', ['runs']), ('cat', ['jumps']), ('dog', ['jumps']), ('fast', ['a']), ('jumps', ['and', 'high']), ('runs', ['fast'])]

>>> bigrama2 = {}
>>> text2 = 'a cat runs as fast as a bicicle'
>>> resultat2 = extreu_bigrames(text2, bigrama2)
>>> bigrama2 == {
...     'a': ['cat', 'bicicle'],
...     'cat': ['runs'],
...     'runs': ['as'],
...     'as': ['fast', 'a'],
...     'fast': ['as']
... }
True
>>> resultat2
[('a', ['cat', 'bicicle']), ('as', ['fast', 'a']), ('cat', ['runs']), ('fast', ['as']), ('runs', ['as'])]

>>> bigrama3 = {}
>>> resultat3 = extreu_bigrames('', bigrama3)
>>> bigrama3 == {}
True
>>> resultat3
[]

>>> bigrama4 = {}
>>> resultat4 = extreu_bigrames('hello', bigrama4)
>>> bigrama4 == {}
True
>>> resultat4
[]