Moved a second piece of code from memory_allocation.rst to the examples directory for testing.

docs/examples/tutorial/memory_allocation/some_memory.pyx

+from cpython.mem cimport PyMem_Malloc, PyMem_Realloc, PyMem_Free
+
+cdef class SomeMemory:
+
+    cdef double* data
+
+    def __cinit__(self, size_t number):
+        # allocate some memory (uninitialised, may contain arbitrary data)
+        self.data = <double*> PyMem_Malloc(number * sizeof(double))
+        if not self.data:
+            raise MemoryError()
+
+    def resize(self, size_t new_number):
+        # Allocates new_number * sizeof(double) bytes,
+        # preserving the current content and making a best-effort to
+        # re-use the original data location.
+        mem = <double*> PyMem_Realloc(self.data, new_number * sizeof(double))
+        if not mem:
+            raise MemoryError()
+        # Only overwrite the pointer if the memory was really reallocated.
+        # On error (mem is NULL), the originally memory has not been freed.
+        self.data = mem
+
+    def __dealloc__(self):
+        PyMem_Free(self.data)  # no-op if self.data is NULL

docs/src/tutorial/memory_allocation.rst

@@ -79,28 +79,6 @@ python process exits.  This is called a memory leak.
 If a chunk of memory needs a larger lifetime than can be managed by a
 ``try..finally`` block, another helpful idiom is to tie its lifetime
 to a Python object to leverage the Python runtime's memory management,
-e.g.::
-
-  cdef class SomeMemory:
-
-      cdef double* data
-
-      def __cinit__(self, size_t number):
-          # allocate some memory (uninitialised, may contain arbitrary data)
-          self.data = <double*> PyMem_Malloc(number * sizeof(double))
-          if not self.data:
-              raise MemoryError()
-
-      def resize(self, size_t new_number):
-          # Allocates new_number * sizeof(double) bytes,
-          # preserving the current content and making a best-effort to
-          # re-use the original data location.
-          mem = <double*> PyMem_Realloc(self.data, new_number * sizeof(double))
-          if not mem:
-              raise MemoryError()
-          # Only overwrite the pointer if the memory was really reallocated.
-          # On error (mem is NULL), the originally memory has not been freed.
-          self.data = mem
-
-      def __dealloc__(self):
-          PyMem_Free(self.data)     # no-op if self.data is NULL
+e.g.:
+
+.. literalinclude:: ../../examples/tutorial/memory_allocation/some_memory.pyx