pygraphviz in depth

graph

1. draw direction rankdir

   1. LR left -> right

   2. RL right -> left

   3. TB top -> bottom

   4. BT bottom -> top

node

1. attrs

   1. shape

       assembly
       box
       box3d
       cds
       circle
       component
       cylinder
       diamond
       doublecircle
       doubleoctagon
       egg
       ellipse
       fivepoverhang
       folder
       hexagon
       house
       insulator
       invhouse
       invtrapezium
       invtriangle
       larrow
       lpromoter
       Mcircle
       Mdiamond
       Msquare
       none
       note
       noverhang
       octagon
       oval
       parallelogram
       pentagon
       plain
       plaintext
       point
       polygon
       primersite
       promoter
       proteasesite
       proteinstab
       rarrow
       rect
       rectangle
       restrictionsite
       ribosite
       rnastab
       rpromoter
       septagon
       signature
       square
       star
       tab
       terminator
       threepoverhang
       trapezium
       triangle
       tripleoctagon
       underline
       utr
      

edge

1. multinode to one

        node1 -> node4;
        node2 -> node4;
        node3 -> node4;
   
        /* equal to */
           
        {node1, node2, node3} -> node4;