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.

George heard about the benefits of a data warehouse. he wants to try implementing one for his organization. however, he is afraid that transferring data to the data warehouse will affect transaction time. which element ensures that transactions are not affected when moving data to a warehouse? when data is transferred to a data warehouse, the a area frees the source system to continue transaction processing.