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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def paginate_sources(owner=None, page=1, page_size=DEFAULT_PAGE_SIZE):
    '''Paginate harvest sources'''
    sources = _sources_queryset(owner=owner)
    page = max(page or 1, 1)
    return sources.paginate(page, page_size)