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CODE WORKSPACE
Raw rows arrive as dicts of strings. Everything downstream would rather have a record whose fields are named, typed and complete — so the conversion happens once, here, and after it nobody writes a defensive .get() again.
Write to_orders(rows) using a dataclass for the record shape. Return the records that satisfy the contract and the rows that cannot.
Function to write
to_orders(rows: list[dict]) -> dictA dict with the contract-satisfying `records` as plain dicts, and the `rejected` rows.
How to approach it
Write the dataclass first. The conversion follows from its fields.
Sample cases
+ 2 held back until you submit
a complete row
Every field present: the record comes back typed, with no warnings.
Input
Argument 1
| order_id | amount | buyer | region |
|---|---|---|---|
| 1042 | 12.50 | Amir | eu |
Returns
{
'records': [
{
'order_id': 1042,
'amount': '12.50',
'buyer': 'Amir',
'region': 'eu',
'warnings': []
}
],
'rejected': []
}optional fields missing
Defaults are applied and each one is recorded as a warning rather than applied silently.
Input
Argument 1
| order_id | amount |
|---|---|
| 1043 | 5.00 |
Returns
{
'records': [
{
'order_id': 1043,
'amount': '5.00',
'buyer': 'unknown',
'region': 'unknown',
'warnings': [
'buyer defaulted',
'region defaulted'
]
}
],
'rejected': []
}no rows
An empty batch produces two empty lists, and does not build a record out of nothing.
Input
Argument 1
[] (empty list)
Returns
{
'records': [],
'rejected': []
}Constraints
order_id (int), amount (a decimal string), buyer and region (text, defaulting to unknown), and warnings (a list).order_id and amount are required. Missing, blank, or unconvertible means the row is rejected as {'row': <index>, 'missing': [<field>]}.amount is parsed with Decimal and returned as a string, so the digits survive and the result can be serialised.<field> defaulted to warnings, so the default is visible rather than silent.order_id, amount, buyer, region, warnings.Worked example
A row with order_id of 1043 and amount of 5.00, and nothing else, satisfies the contract.
It comes back with buyer and region both unknown — and with two warnings saying so. That second half is the design decision: a default applied silently is indistinguishable downstream from a value the source actually sent, and the warning is what lets somebody notice the producer stopped sending a column.
What this tests
That a dataclass is a contract rather than a shorthand for __init__, that a mutable field default needs default_factory or every instance shares one list, and that a default is a decision worth recording.
to_orders(rows: list[dict]) -> dictSubmit for review to find out what your query gets right, what it gets wrong, and how it compares with the best working query for this exercise.
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