What does the / sign mean in the signature of numpy functions like sqrt?

Question

What does sign / sign mean in numpy function signature? The sign / appears between positional and keword arguments.

For instance:

sqrt(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])
power(x1, x2, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj])

Online documentation numpy.sqrt - and numpy. nutrition function .