import string
import random


def generate_string( length=10, letters=string.ascii_letters ):
    """
    Generate a random string

    Arguments
    ---------
    length: int (optional, default 10)
    letters: string (optional, default is all ascii letters)

    Returns
    -------
    string
        random string
    """
    return u''.join(
        random.choice(  letters ) for x in range( length ) )