sage: A = x.subalgebra_generated_by(orthonormalize_basis=True)
sage: y = A.random_element()
sage: y.operator()(A.one()) == y
sage: A = x.subalgebra_generated_by(orthonormalize_basis=True)
sage: y = A.random_element()
sage: y.operator()(A.one()) == y
# If our superalgebra is a subalgebra of something else, then
# these vectors won't have the right coordinates for
# V.span_of_basis() unless we use V.from_vector() on them.
# If our superalgebra is a subalgebra of something else, then
# these vectors won't have the right coordinates for
# V.span_of_basis() unless we use V.from_vector() on them.