try:
    from Interface import Interface
except ImportError:
    # for Zope versions before 2.6.0
    from Interface import Base as Interface

class IRepresentable(Interface):
    """
    Interface for representable content.
    """

    def isRepresentation():
        """
        return True if this object is used as representation, 0 otherwise
        """

    def addRepresentation(**kwargs):
        """
        Add a new representation of this content.
        """

    def removeRepresentation(repr_id):
        """
        Removes a representation. 
        """

    def getRepresentation(repr_id):
        """
        Return an object that is a representation of self
        """

    def getRepresentations():
        """
        Return a list of (object, wf_state)
        """

    def isCanonicalRepresentation():
        """
        boolean, is this the first representation of the content.
        """

    def getCanonicalRepresentation():
        """
        Return the first representation of this content.
        """

    def initializeRepresentation():
        """
        Initializes the object as a representation, would typically be called by
        addRepresentation.
        """