frappe.get_doc("Lead", {"email_id": ""}) DoesNotExistError

Hello Guys,

dose somebody know why i get a DoesNotExistError exception and not new_lead?
What wold bee a right approach?

Thanks in advance

data = frappe.form_dict

# Search for the lead by email ID
existing_lead = frappe.get_doc("Lead", {"email_id":})

if not existing_lead:
    # Create a new lead
    new_lead = frappe.get_doc({
        "doctype": "Lead",
        "first_name": "John",
        "email_id": "",
    frappe.response['message'] = new_lead
    frappe.response['message'] = existing_lead

ERPNext: v14.14.0