code: def _element_at_zoom(name, element, zoom):
          
          # If element is a dictionary, analyze subitems.
          if isinstance(element, dict):
              if "format" in element:
                  # we have an input or output driver here
                  return element
              out_elements = {}
              for sub_name, sub_element in element.items():
                  out_element = _element_at_zoom(sub_name, sub_element, zoom)
                  if name == "input":
                      out_elements[sub_name] = out_element
                  elif out_element is not None:
                      out_elements[sub_name] = out_element
              # If there is only one subelement, collapse unless it is
              # input. In such case, return a dictionary.
              if len(out_elements) == 1 and name != "input":
                  return next(iter(out_elements.values()))
              # If subelement is empty, return None
              if len(out_elements) == 0:
                  return None
              return out_elements
          # If element is a zoom level statement, filter element.
          elif isinstance(name, str):
              if name.startswith("zoom"):
                  return _filter_by_zoom(
                      conf_string=name.strip("zoom").strip(), zoom=zoom,
                      element=element)
              # If element is a string but not a zoom level statement, return
              # element.
              else:
                  return element
          # Return all other types as they are.
          else:
              return element
docs: Return the element filtered by zoom level.
  
          - An input integer or float gets returned as is.
          - An input string is checked whether it starts with "zoom". Then, the
            provided zoom level gets parsed and compared with the actual zoom
            level. If zoom levels match, the element gets returned.
          TODOs/gotchas:
          - Elements are unordered, which can lead to unexpected results when
            defining the YAML config.
          - Provided zoom levels for one element in config file are not allowed
            to "overlap", i.e. there is not yet a decision mechanism implemented
            which handles this case.