docs: def leaves(self, column_name):
          """
          :param column_name:
          :return: ALL COLUMNS THAT START WITH column_name, NOT INCLUDING DEEPER NESTED COLUMNS
          """
          clean_name = unnest_path(column_name)
  
          if clean_name != column_name:
              clean_name = column_name
              cleaner = lambda x: x
          else:
              cleaner = unnest_path
  
  
          columns = self.columns
          # TODO: '.' IMPLIES ALL FIELDS FROM ABSOLUTE PERPECTIVE, ALL OTHERS ARE A RELATIVE PERSPECTIVE
          # TODO: HOW TO REFER TO FIELDS THAT MAY BE SHADOWED BY A RELATIVE NAME?
          for path in reversed(self.query_path) if clean_name == '.' else self.query_path:
              output = [
                  c
                  for c in columns
                  if (
                      (c.name != "_id" or clean_name == "_id") and
                      (
                          (c.jx_type == EXISTS and column_name.endswith("." + EXISTS_TYPE)) or
                          c.jx_type not in OBJECTS or
                          (clean_name == '.' and c.cardinality == 0)
                      ) and
                      startswith_field(cleaner(relative_field(c.name, path)), clean_name)
                  )
              ]
              if output:
                  return set(output)
          return set()