Load the functions into the scope.

def load_functions(self, tree):
        """Load the functions into the scope."""
        for child in tree.children:
            if isinstance(child, FunctionDeclaration):
                if self.table[child.identifier.name] is not None:
                    raise SementicError(
                        f"Function `{child.identifier.name}` already declared."
                    )
                self.table[child.identifier.name] = FunctionSymbol(child)