Typing Functions
----------------
-Python function calls can be expensive--in Cython doubly so because
+Python function calls can be expensive -- in Cython doubly so because
one might need to convert to and from Python objects to do the call.
In our example above, the argument is assumed to be a C double both inside f()
and in the call to it, yet a Python ``float`` object must be constructed around the
=========
In addition to the ``.pyx`` source files, Cython uses ``.pxd`` files
-which work like C header files--they contain Cython declarations
+which work like C header files -- they contain Cython declarations
(and sometimes code sections) which are only meant for inclusion by
Cython modules. A ``pxd`` file is imported into a ``pyx`` module by
using the ``cimport`` keyword.