Generate a unique username, containing 8 - 10 characters, made of both numbers and letters.
Sure, one possible unique username could be: J7K9L6XZ01
Complete the following task based on the instruction and optional input provided.### Instruction:
Generate a unique username, containing 8 - 10 characters, made of both numbers and letters.

### Output:
Sure, one possible unique username could be: J7K9L6XZ01