def _getPhrase( self, i, sentence, NPlabels ):
        ''' Fetches the full length phrase from the position i
            based on the existing NP phrase annotations (from 
            NPlabels);
            Returns list of sentence tokens in the phrase, and 
            indices of the phrase;
        ''' 
        phrase  = []
        indices = []
        if 0 <= i and i < len(sentence) and NPlabels[i] == 'B':
            phrase  = [ sentence[i] ]
            indices = [ i ]
            j = i + 1
            while ( j < len(sentence) ):
                if NPlabels[j] in ['B', '']:
                    break
                else:
                    phrase.append( sentence[j] )
                    indices.append( j )
                j += 1
        return phrase, indices
Fetches the full length phrase from the position i
            based on the existing NP phrase annotations (from 
            NPlabels);
            Returns list of sentence tokens in the phrase, and 
            indices of the phrase;