Retrieves one or more attributes of a problem.

p = xpress.problem()
p.read("example.lp")
print(p.getAttrib('cols'), "columns and ",
       p.getAttrib('rows'), "rows")
prob_attrib = p.getAttrib()
attr_subset = p.getAttrib(['cols', 'rows'])

This function can be passed either a single attribute name, whose value will be returned, or a list of attribute names, in which case the return value is a dictionary associating each key in the list with its value. If no argument is provided, a dictionary containing all attributes of the problem will be returned.