Example of boost/python/call_method.hpp does not compile

I compilled the my_module.cpp file with the following command:
`
gcc -o my_module.o my_module.cpp -c -Wall -fPIC -I/usr/include/python3.6
`

This resulted in the following error:
```
my_module.cpp: In member function ‘virtual const char* Base_callback::class_name() const’:
my_module.cpp:31:44: error: ‘call_method’ was not declared in this scope
char const* class_name() const { return call_method(m_self, "class_name"); }
^~~~~~~~~~~
my_module.cpp:31:56: error: expected primary-expression before ‘char’
char const* class_name() const { return call_method(m_self, "class_name"); }
^~~~
my_module.cpp:31:56: error: expected ‘;’ before ‘char’
my_module.cpp:31:67: error: expected unqualified-id before ‘>’ token
char const* class_name() const { return call_method(m_self, "class_name"); }
^
my_module.cpp:31:67: error: expected initializer before ‘>’ token
my_module.cpp: In function ‘void init_module_tryout()’:
my_module.cpp:40:5: error: ‘def’ was not declared in this scope
def("is_base", is_base);
^~~
makefile:16: recipe for target 'my_module.o' failed
```

The solution was to add the following 2 include statements:
```
#include
#include
```