Build the dependencies for this module.

        Parse the code with ast, find all the import statements, convert
        them into Dependency objects.

def build_dependencies(self):
        """
        Build the dependencies for this module.

        Parse the code with ast, find all the import statements, convert
        them into Dependency objects.
        """
        highest = self.dsm or self.root
        if self is highest:
            highest = LeafNode()
        for _import in self.parse_code():
            target = highest.get_target(_import['target'])
            if target:
                what = _import['target'].split('.')[-1]
                if what != target.name:
                    _import['what'] = what
                _import['target'] = target
            self.dependencies.append(Dependency(source=self, **_import))