just as an added help ,
to write or edit dictionaries in dynamo python u need to add the following imports
> import sys
> import clr
> import System.Collections.Generic
> Dictionary = System.Collections.Generic.Dictionary[System.String,System.Object]()
>
> # The inputs to this node will be stored as a list in the IN variables.
> dict = IN[0]
>
> # Place your code below this line
>
> # Assign your output to the OUT variable.
> OUT = dict