When a parameter of a Python function is declared to have a C data type, it is
passed in as a Python object and automatically converted to a C value, if
-possible. Automatic conversion is currently only possible for numeric types,
+possible. In other words, the definition of `spam` above is equivalent to writing::
+
+ def spam(python_i, python_s):
+ int i = python_i
+ char* s = python_s
+ ...
+
+Automatic conversion is currently only possible for numeric types,
string types and structs (composed recusively of any of these types);
attempting to use any other type for the parameter of a
Python function will result in a compile-time error.