Implemented constraints
Typo in message
Create dictionaries to store incoming and outgoing edges from vertices
Added method to add an iterable of placements and migrated placement_id from string to tuple
Implement resources. Store value from constructor attribute and return it in the getter
Changed Iterable to iterable
Created skeleton for testing
Store subedge routing info in a list, and in a dictionary with 'key' as key :) Need to check get_subedge_info_by_key