Correct occurance → occurrence; extracted from patch by Georg Brandl

Objects/bytearrayobject.c

@@ -1990,7 +1990,7 @@ replace(PyByteArrayObject *self,
     }
 
     if (to_len == 0) {
-        /* delete all occurances of 'from' bytes */
+        /* delete all occurrences of 'from' bytes */
         if (from_len == 1) {
             return replace_delete_single_character(
                     self, from_s[0], maxcount);
@@ -2399,7 +2399,7 @@ bytearray_pop(PyByteArrayObject *self, PyObject *args)
 PyDoc_STRVAR(remove__doc__,
 "B.remove(int) -> None\n\
 \n\
-Remove the first occurance of a value in B.");
+Remove the first occurrence of a value in B.");
 static PyObject *
 bytearray_remove(PyByteArrayObject *self, PyObject *arg)
 {

Objects/stringobject.c

@@ -2775,7 +2775,7 @@ replace(PyStringObject *self,
     }
 
     if (to_len == 0) {
-        /* delete all occurances of 'from' string */
+        /* delete all occurrences of 'from' string */
         if (from_len == 1) {
             return replace_delete_single_character(
                 self, from_s[0], maxcount);