Looks like this is marginally faster.

```python
#!/usr/bin/env python
""" Timing stuff.

::
    $ python timeittest.py
    set(map(str.strip, ['wat '] * 200))
    30.9805839062
    set([s.strip() for s in ['wat '] * 200])
    31.884624958
"""

import timeit


def measure(stmt):
    print stmt
    results = timeit.timeit(stmt)
    print results


measure("set(map(str.strip, ['wat '] * 200))")
measure("set([s.strip() for s in ['wat '] * 200])")
```