'Gets the branch that we want to pull.
This may raise a ValueError if the specification is inconsistent.
This is determined lazily rather than at construction to be consistent
with the push_branch property.'

@property
def pull_branch(self):

    if self.__options.pull_origin:
        if (self.__options.pull_branch and (self.__options.pull_branch != 'master')):
            raise ValueError('--pull_origin    is    incompatible    with    --pull_branch={branch}'.format(branch=self.__options.pull_branch))
        return 'master'
    return self.__options.pull_branch
