Remove all warnings from documentation

beat/backend/python/algorithm.py

beat/backend/python/baseformat.py

beat/backend/python/data.py

beat/backend/python/data_loaders.py

beat/backend/python/database.py

beat/backend/python/dataformat.py

beat/backend/python/dbexecution.py

beat/backend/python/executor.py

beat/backend/python/hash.py

beat/backend/python/inputs.py

beat/backend/python/library.py

beat/backend/python/loader.py

beat/backend/python/outputs.py

doc/api.rst

doc/conf.py