Implemented 'identity' function.
Implemented 'last' function.
Implemented 'each' function.
Implemented 'filter' function.
Implemented 'negate' and 'reject' functions.
Implemented 'uniq' function.
Implemented 'map' function.
Implemented 'invoke' function.
Implemented 'reduce' function.
Edited order of arguments for 'reduce' function.
Refactored 'reduce' function to handle empty 'accumulator' argument more effectively, allowing 'contains' function (which uses 'reduce') to pass all test conditions.
Implemented 'every' function.
Implemented 'some' function.
Implemented 'extend' function.
Implemented 'defaults' function.
Implemented 'memoize' function.
Implemented 'delay' function.
Implemented 'shuffle' function.
Implemented 'sortBy' function.
Implemented 'zip' function.