Given a string of module names, it will return the 'include' directories
    essential to their compilation as long as the module has the conventional
    'get_include' function.

def getDirsToInclude(string):
    """
    Given a string of module names, it will return the 'include' directories
    essential to their compilation as long as the module has the conventional
    'get_include' function.
    """
    dirs = []
    a = string.strip()
    obj = a.split('-')

    if len(obj) == 1 and obj[0]:
        for module in obj:
            try:
                exec('import {}'.format(module))
            except ImportError:
                raise FileNotFoundError("The module '{}' does not"
                                        "exist".format(module))
            try:
                dirs.append('-I{}'.format(eval(module).get_include()))
            except AttributeError:
                print(NOT_NEEDED_MESSAGE.format(module))
    return dirs