'Returns those morphisms (and their properties) which are
sufficiently meaningful to be drawn.
Examples
>>> from sympy.categories import Object, NamedMorphism
>>> from sympy.categories import Diagram, DiagramGrid
>>> A = Object("A")
>>> B = Object("B")
>>> C = Object("C")
>>> f = NamedMorphism(A, B, "f")
>>> g = NamedMorphism(B, C, "g")
>>> diagram = Diagram([f, g])
>>> grid = DiagramGrid(diagram)
>>> grid.morphisms
{NamedMorphism(Object("A"), Object("B"), "f"): EmptySet(),
NamedMorphism(Object("B"), Object("C"), "g"): EmptySet()}'

@property
def morphisms(self):

    return self._morphisms
