code: def source_schema(self, sources=None, tables=None, clean=False):
          
  
          sources = self._resolve_sources(sources, tables, None,
                                          predicate=lambda s: s.is_processable)
  
          for source in sources:
              source.update_table()
              self.log("Creating source schema for '{}': Table {},  {} columns"
                       .format(source.name, source.source_table.name, len(source.source_table.columns)))
  
          self.commit()
docs: Process a collection of ingested sources to make source tables.