import random


def gen_rand_seq(length):
    """
    Generate a random DNA sequence of defined length
    
    Parameters
    ----------
    length : int
    
    Returns
    ---------
    seq : string
         Random DNA sequence
    """

    nt = ['A','T','C','G'] #nucleotides
    seq = ''.join(random.choice(nt) for i in range(length))
    return(seq)