Mapping validation fails if a user-defined default value is assigned to an output port.
The mapping fails in the following situations:
An output port is not assigned a value in the Python code.
The data types in corresponding input and output ports are not the same, and the Python code does not convert the data type in the input port to the data type in the output port.
The Python transformation contains decimal ports and high precision is enabled in the mapping.
The Data Integration Service does not validate Python code.