Unexpected datetime behavior

I have a Django project where I used the strftime function like this in models.py:

class Email(models.Model):
    user = models.ForeignKey("User", on_delete=models.CASCADE, related_name="emails")
    sender = models.ForeignKey("User", on_delete=models.PROTECT, related_name="emails_sent")
    recipients = models.ManyToManyField("User", related_name="emails_received")
    subject = models.CharField(max_length=255)
    body = models.TextField(blank=True)
    timestamp = models.DateTimeField(auto_now_add=True)
    read = models.BooleanField(default=False)
    archived = models.BooleanField(default=False)

    def serialize(self):
        return {
            "id": self.id,
            "sender": self.sender.email,
            "recipients": [user.email for user in self.recipients.all()],
            "subject": self.subject,
            "body": self.body,
            "timestamp": self.timestamp.strftime("%b %-d %Y, %-I:%M %p"),
            "read": self.read,
            "archived": self.archived
        }

However, for some reason this returns a ValueError, even though according to a documentation (https://www.programiz.com/python-programming/datetime/strftime) this is a valid format string. Once I removed all the dashes, it worked normally. Why doesn’t this work? Do I need to import a module or something? Thanks.

Answer

To @jsonharper’s comment, here’s a link to the official Python 3 docs: https://docs.python.org/3.0/library/datetime.html#strftime-behavior As he pointed out, that site notes platform variations are common and does not list “-” as a commonly-accepted format specifier.

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Answer