Improve docstrings and type hints in scheduling_cosine_dpmsolver_multistep.py (#12936)
* docs: improve docstring scheduling_cosine_dpmsolver_multistep.py
* Update src/diffusers/schedulers/scheduling_cosine_dpmsolver_multistep.py
Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
* Update src/diffusers/schedulers/scheduling_cosine_dpmsolver_multistep.py
Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
* fix
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Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>