def _element_constructor_(self, x):
"""
TESTS::
sage: f(x) = x+1; g(y) = y+1
sage: f.parent()(g)
x |--> y + 1
sage: g.parent()(f)
y |--> x + 1
sage: f(x) = x+2*y; g(y) = y+3*x
sage: f.parent()(g)
x |--> 3*x + y
sage: g.parent()(f)
y |--> x + 2*y
"""
return SymbolicRing._element_constructor_(self, x)
def _element_constructor_(self, x):
"""
TESTS::
sage: f(x) = x+1; g(y) = y+1
sage: f.parent()(g)
x |--> y + 1
sage: g.parent()(f)
y |--> x + 1
sage: f(x) = x+2*y; g(y) = y+3*x
sage: f.parent()(g)
x |--> 3*x + y
sage: g.parent()(f)
y |--> x + 2*y
"""
return SymbolicRing._element_constructor_(self, x)
