human
Here's a good function header given the following:
I wrote the below code

    def getter(index):
        data = index._data
        if (len(data) == 0):
            return True
        u = data[0]
        for v in data:
            if (v < u):
                return False
            v = u
        return True
    return getter

What's a good function header?
assistant
#Here's a good function header.

@overload_attribute(IndexType, 'is_monotonic_increasing')
def index_is_monotonic_increasing(typ):