code: def register(matcher, *aliases):
      
      docstr = matcher.__doc__ if matcher.__doc__ is not None else ''
      helpmatchers[matcher] = docstr.strip()
  
      for alias in aliases:
          matchers[alias] = matcher
          # Map a normalized version of the alias
          norm = normalize(alias)
          normalized[norm] = alias
          # Map a version without snake case
          norm = norm.replace('_', '')
          normalized[norm] = alias
docs: Register a matcher associated to one or more aliases. Each alias
          given is also normalized.