def get_complement(nucleotide):
    """ Returns the complementary nucleotide
        nucleotide: a nucleotide (A, C, G, or T) represented as a string
        returns: the complementary nucleotide
    >>> get_complement('A')
    'T'
    >>> get_complement('C')
    'G'
    >>> get_complement('G')
    'C'
    >>> get_complement('T')
    'A'
    >>> get_complement('L')
    -1
    """
    if nucleotide == 'A': #change A to T
        return 'T'
    elif nucleotide == 'T': # T to A
        return 'A'
    elif nucleotide == 'C': # C to G
        return 'G'
    elif nucleotide == 'G': # G to C
        return 'C'
#should I have a negative one, you didn't feed me a valid dna sequence
    else:
        return -1