Build a Mage data pipeline with conditional block execution and dynamic child blocks for branching ETL logic

Steps

1. Create a new Mage pipeline and add a Data Loader block as the pipeline root; connect it to a Transformer block via the pipeline graph editor
2. Add a Conditional block by selecting Block Type > Conditional in the editor; implement the condition function to return True or False based on upstream block output
3. Wire the Conditional block between upstream and downstream blocks; Mage skips all downstream blocks if the condition returns False, enabling branch pruning
4. Use Dynamic blocks to generate child blocks at runtime: decorate a block with @data_exporter and return a list of items from a block tagged as dynamic; Mage creates one child execution per item
5. Configure reduce_output=True on the block that follows a Dynamic block to collect child outputs back into a single list for downstream processing
6. Trigger the pipeline via the Mage UI Run button or the Mage API POST /pipelines/{pipeline_uuid}/pipeline_runs to execute with optional runtime variables