with the following server script I was able to create Purchase Receipt Doctype with Child table.
Note the child table from one Purchase Receipt was copied to another new Purchase receipt
for d in doc.get('items'):
if d.item_code:
pr = frappe.get_doc({
"doctype" : "Purchase Receipt",
"supplier": doc.supplier,
"supplier_name": doc.supplier_name,
"posting_date": doc.posting_date,
"posting_time": doc.posting_time,
"items": [
{
"item_code" : d.item_code,
"description" : d.description,
"qty": d.qty,
"uom": d.uom,
"stock_uom": d.stock_uom,
"conversion_factor": d.conversion_factor,
"rate": d.rate,
"amount": d.amount,
"base_rate": d.base_rate,
"base_amount" : d.base_amount
}
]
})
pr.insert()
pr.save()