b'abc'.partition(':') raises a confusing TypeError('expected an object with the buffer interface'): what is a buffer? what is the buffer interface?

The error comes from PyObject_AsCharBuffer() which is used by:
 - bytes methods: partition, rpartition, find, index, rfind, rindex, count, translate, replace, startswith, endswith
 - complex(): raise a better but incomplete error message on error ("complex() arg is not a string"), incomplete because number is not mentionned
 - float(): raise a better error message on error ("float() argument must be a string or a number")
 - PyArg_Parse*() with the "e" format -> posix.spawnvpe(), imp.load_compiled(), imp.load_source(), imp.load_package()

The error message should be changed to something mentioning classic Python terms. Eg. TypeError("expected bytes, bytearray or buffer compatible object").