'MatrixImplementation models a cell in the matrix
This models the current state of a target for a specific feature
:param status: One off complete, partial, missing, unknown.
See the RST docs for a definition of those.
:param notes: Arbitrary string describing any caveats of the
implementation. Mandatory if status is \'partial\'.
:param release: Letter of the release entry was last updated.
i.e. m=mitaka, c=cactus. If not known it is None.'

def __init__(self, status=STATUS_MISSING, notes=None, release=None):

    self.status = status
    self.notes = notes
    self.release = release
