+ If a ``lattice`` was given, it is actually used::
+
+ sage: L = ToricLattice(3, 'M')
+ sage: schur_cone(3, lattice=L)
+ 2-d cone in 3-d lattice M
+
+ Unless the rank of the lattice disagrees with ``n``::
+
+ sage: L = ToricLattice(1, 'M')
+ sage: schur_cone(3, lattice=L)
+ Traceback (most recent call last):
+ ...
+ ValueError: lattice rank=1 and dimension n=3 are incompatible
+