def histogram(test):
    """Given a string representing a space separated lowercase letters, return a dictionary
    of the letter with the most repetition and containing the corresponding count.
    If several letters have the same occurrence, return all of them.
    
    Example:
    histogram('a b c') == {'a': 1, 'b': 1, 'c': 1}
    histogram('a b b a') == {'a': 2, 'b': 2}
    histogram('a b c a b') == {'a': 2, 'b': 2}
    histogram('b b b b a') == {'b': 4}
    histogram('') == {}

    """
    dict1={}
    list1=test.split(" ")
    t=0

    for i in list1:
        if(list1.count(i)>t) and i!='':
            t=list1.count(i)
    if t>0:
        for i in list1:
            if(list1.count(i)==t):
                
                dict1[i]=t
    return dict1