class_docstr: Implements the TAB-completion for the %%opts magic.
code: def line_completer(cls, line, completions, compositor_defs):
      sorted_keys = sorted(completions.keys())
      type_keys = [key for key in sorted_keys if ("." not in key)]
      completion_key, suggestions = cls.dotted_completion(
          line, sorted_keys, compositor_defs
      )
  
      verbose_openers = ["style(", "plot[", "norm{"]
      if suggestions and line.endswith("."):
          return [f"{completion_key}.{el}" for el in suggestions]
      elif not completion_key:
          return (
              type_keys + list(compositor_defs.keys()) + verbose_openers
          )
  
      if cls._inside_delims(line, "[", "]"):
          return [kw + "=" for kw in completions[completion_key][0]]
  
      if cls._inside_delims(line, "{", "}"):
          return ["+axiswise", "+framewise"]
  
      style_completions = [
          kw + "=" for kw in completions[completion_key][1]
      ]
      if cls._inside_delims(line, "(", ")"):
          return style_completions
  
      return type_keys + list(compositor_defs.keys()) + verbose_openers
  
imports: import sys
  import time
  from IPython.core.magic import Magics, line_cell_magic, line_magic, magics_class
  from IPython.display import HTML, display
  from ..core.options import Options, Store, StoreOptions, options_policy
  from ..core.pprint import InfoPrinter
  from ..operation import Compositor
  from IPython.core import page
label_desc: Use image node_id 5 for calling the OptsCompleter obj's underlying member method code with example usage: obj.line_completer(cls, line, completions, compositor_defs) and returns: unknown, unknown, unknown, list, style_completions, unknown