icache.getOrSet('test', 'test'); /* Type: any */
icache.getOrSet('test', () => 'test'); /* Type: any */
icache.getOrSet('test', () => Promise.resolve()); /* Type: any */
	
icache.getOrSet<string>('test', 'test'); /* Type: string | undefined */
icache.getOrSet<string>('test', 42); /* No Error, Type: string | undefined */
icache.getOrSet<string>('test', () => 'test'); /* Type: string | undefined */
icache.getOrSet<string>('test', () => Promise.resolve()); /* Type: string | undefined */

icache.getOrSet('test', 'test'); /* Type: 'test' */
icache.getOrSet('test', () => 'test'); /* Type: string */
icache.getOrSet('test', () => Promise.resolve()); /* Type: undefined */

icache.getOrSet<string>('test', 'test'); /* Type: string */
icache.getOrSet<string>('test', 42); /* Type error: '42' is not assignable to parameter of type 'string' */
icache.getOrSet<string>('test', () => 'test'); /* Type: string */
icache.getOrSet<string>('test', () => Promise.resolve()); /* Type error: '() => Promise<void>' is not assignable to parameter of type 'string' */
icache.getOrSet<string>('test', () => new Promise<string>(() => {})); /* Type: undefined */