define a function named sum_values_by_year with two parameters. the first parameter will be a list of dictionaries (the data). the second parameter will be a string (a key). this function must return a dictionary. the keys of the dictionary are the year strings that appear in the dictionaries. the values must be the sum of the dictionaries' values associated with the second parameter for that year.

What is transmission control protocol/internet protocol (tcp/ip)? software that prevents direct communication between a sending and receiving computer and is used to monitor packets for security reasons a standard that specifies the format of data as well as the rules to be followed during transmission a simple network protocol that allows the transfer of files between two computers on the internet a standard internet protocol that provides the technical foundation for the public internet as well as for large numbers of private networks