getAttr ( attrname )
Query the value of a general constraint attribute. The full list of available attributes can be found in the Attributes section.
AttributeError if the requested attribute doesn't
exist or can't be queried.
GurobiError if there is a problem with the
GenConstr object (e.g., it was removed from the model).
attrname: The attribute being queried.
The current value of the requested attribute.