"""
    Implement the function unique_in_order which takes as argument a sequence and returns a list of items without any elements with the same value next to each other and preserving the original order of elements.
    
    For example:
    
    unique_in_order('AAAABBBCCDAABBB') == ['A', 'B', 'C', 'D', 'A', 'B']
    unique_in_order('ABBCcAD')         == ['A', 'B', 'C', 'c', 'A', 'D']
    unique_in_order([1,2,2,3,3])       == [1,2,3]
"""

def unique_in_order(input_iterable):
    out = [input_iterable[0]]
    for i in range(1,len(input_iterable)):    
        if input_iterable[i] != input_iterable[i-1]:
            out.append(input_iterable[i])
    return out

