Mapping a dictionary:
D = {'food': 'Spam', 'quantity':4} #build with {}
D = dict(food='Spam', quantity=4) #build with dict()
D={}
D['key'] = 'value' #add key,value to a dict.
#Sorting Keys:
for key in sorted(D):
print(key, '=>', D[key])
#Missing Keys:
value = D.get('x', 0) #0 for default if None
value= D['key'] if 'x' in D else 0