Understanding list slicing and manipulation

Question

I have gotten the following code from the book: "Learn Python Programming":

def sortM(v,parts=2):
    assert parts>1, "parts should be greater or equal than 2"
    if len(v)<=1:
        return v
    chunk_len=max(1,len(v)//parts)
    chunks=(
            sortM(v[k:k+chunk_len],parts=parts)
            for k in range(0,len(v),chunk_len)
            )
    return multi_merge(*chunks)

def multi_merge(*v):
    return reduce(merge,v)

def merge(v1,v2):
    v=[]
    h=k=0
    len_v1,len_v2=len(v1),len(v2)
    while h<len_v1 or k<len_v2:
        if k==len_v2 or (h<len_v1 and v1[h]<v2[k]):
            v.append(v1[h])
            h=h+1
        else:
            v.append(v2[k])
            k=k+1
    return v

This code is the draft part for performing mergesort by using concurrency. So far I understand the simple mergesort, but I have some questions regarding the code that the author does not specify. My questions are related to these statements:

chunks=(
                sortM(v[k:k+chunk_len],parts=parts)
                for k in range(0,len(v),chunk_len)
                )

I have tried to print what chunks contain but only I get like objects with no meaning. So in this part, what the author is doing? For what I see is making a recursive call to sortM() with a slice of the original list, is it like that?

Also, does multi_merge(*chunks) is putting into a tuple the two lists or lists generated by chunks?