Some interesting Pymel Attribute Functions

isFreeToChange(checkParents=True, checkChildren=True)

Returns true if the plug’s value is allowed to be set directly. A plug isFreeToChange if it is not locked, and it is not a destination or if it is a destination, then it must be a special case (such as connected to an anim curve).

Parameters:	checkParents : bool Check parent plugs. checkChildren : bool Check child plugs.
Return type:	PyNode.FreeToChangeState

isFromReferencedFile()

This method determines whether this plug came from a referenced file. A plug is considered to have come from a referenced file if it is connected and that connection was made within a referenced file.

Return type:	bool

numConnectedElements()

Return the total number of connected element plugs belonging to this array plug.

Return type:	int

connected element plugs belonging to this array plug.