Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Name the standard yarn weight system for 7 wpi

### Inputs:
table_name: table, columns: ['Standard Yarn Weight System', 'Yarn Type (US)', 'Ply (UK, NZ, AU)', 'm/100g', 'Wraps Per Inch (WPI)']

### Response:
SELECT Standard Yarn Weight System FROM table WHERE Wraps Per Inch (WPI) = 7 wpi