import random
import string


def randomString(n = 10):
    """
    Generate a random string of form [a-zA-Z]{n}(ascii letters of length n).

    Parameters
    ----------
    n : int, default 10
        The length of the random string.
    
    Returns
    -------
    str
        A random string consisting ascii letters of length n.
    """
    return ''.join(random.choice(string.ascii_letters) for i in range(n))