Limit the text input of editable QComboBox

Question

I want to limit the possibility of text-input to the text of the combobox items.

from PyQt5.QtWidgets import QApplication, QComboBox

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    combo = QComboBox()
    combo.setEditable(True)
    combo.insertItems(0, ['Bob', 'Anne', 'Tim'])

    combo.show()
    sys.exit(app.exec_())

In the combobox above, I will not be able to type in e.g. 'Peter' or any other string that is unlike Bob, Anne or Tim.

EDIT:

I have already tried this code, but I failed and I don't know if I am on the right way:

from PyQt5.QtGui import QValidator
from PyQt5.QtWidgets import QApplication, QComboBox

class Validator(QValidator):

    names = ['Bob', 'Anne', 'Tim']

    def validate(self, _text, _pos):

        for name in self.names:
            if _text == name[0:_pos]:

                print(f"match")
                return QValidator.Acceptable
            return QValidator.Intermediate

if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    combo = QComboBox()
    combo.setEditable(True)
    combo.insertItems(0, ['Bob', 'Anne', 'Tim'])

    c_validator = Validator(combo.lineEdit())
    combo.setValidator(c_validator)

    combo.show()
    sys.exit(app.exec_())

This code runs into the error: 'TypeError: invalid result from Validator.validate()'

Additional explanation:

In the picture below you can see a combobox where you can enter a font style.

I have inputed here the three letters a, r and i. After pressing the return- or the tabulator-key the item 'Arial' is selected:

But in this combobox I can also input 'nonsens'. It does nothing! But to prevent an (inexperienced) user to input wrong stuff, I would like this behaviour.