'Returns the \'measure\' of stem, per definition in the paper
From the paper:
A consonant will be denoted by c, a vowel by v. A list
ccc... of length greater than 0 will be denoted by C, and a
list vvv... of length greater than 0 will be denoted by V.
Any word, or part of a word, therefore has one of the four
forms:
CVCV ... C
CVCV ... V
VCVC ... C
VCVC ... V
These may all be represented by the single form
[C]VCVC ... [V]
where the square brackets denote arbitrary presence of their
contents. Using (VC){m} to denote VC repeated m times, this
may again be written as
[C](VC){m}[V].
m will be called the \measure\ of any word or word part when
represented in this form. The case m = 0 covers the null
word. Here are some examples:
m=0    TR,  EE,  TREE,  Y,  BY.
m=1    TROUBLE,  OATS,  TREES,  IVY.
m=2    TROUBLES,  PRIVATE,  OATEN,  ORRERY.'

def _measure(self, stem):

    cv_sequence = u''
    for i in range(len(stem)):
        if self._is_consonant(stem, i):
            cv_sequence += u'c'
        else:
            cv_sequence += u'v'
    return cv_sequence.count(u'vc')
