'Get the translations for a source language phrase
:param src_phrase: Source language phrase of interest
:type src_phrase: tuple(str)
:return: A list of target language phrases that are translations
of ``src_phrase``, ordered in decreasing order of
likelihood. Each list element is a tuple of the target
phrase and its log probability.
:rtype: list(PhraseTableEntry)'

def translations_for(self, src_phrase):

    return self.src_phrases[src_phrase]
