-and END in OBJECT (which defaults to the current buffer).
-Attributes specified by FACE take precedence over existing
-attributes unless BELOW is non-nil. FACE must be a face name (a
-symbol or string), a property list of face attributes, or a list
-of these. For convenience when applied to strings, this returns
-OBJECT."
+and END in OBJECT. Attributes specified by FACE take precedence
+over existing attributes unless BELOW is non-nil.
+
+OBJECT may be a string, a buffer, or nil (which means the current
+buffer). If object is a string, START and END are 0-based;
+otherwise they are buffer positions (integers or markers). FACE
+must be a face name (a symbol or string), a property list of face
+attributes, or a list of these. If START and/or END are omitted,
+they default to the beginning/end of OBJECT. For convenience
+when applied to strings, this returns OBJECT."