'Retrieve a layer that is part of the model.
Returns a layer based on either its name (unique)
or its index in the graph. Indices are based on
order of horizontal graph traversal (bottom-up).
# Arguments
name: string, name of layer.
index: integer, index of layer.
# Returns
A layer instance.'

def get_layer(self, name=None, index=None):

    if (not self.built):
        self.build()
    return self.model.get_layer(name, index)
