[Keyword argument] vertex_shape [Purpose] Shape of the vertex. Known shapes are: rectangle, circle, hidden, triangle-up, triangle-down. Several aliases are also accepted, see drawing.known_shapes. [Attribute name] 
shape
c o l o r
l a b e l
l a b e l _ a n g l e
l a b e l _ c o l o r
l a b e l _ d i s t
l a b e l _ s i z e
o r d e r
s h a p e
s i z e