code: def lookup(alias):
      
  
      if alias in matchers:
          return matchers[alias]
      else:
          norm = normalize(alias)
          if norm in normalized:
              alias = normalized[norm]
              return matchers[alias]
  
      # Check without snake case
      if -1 != alias.find('_'):
          norm = normalize(alias).replace('_', '')
          return lookup(norm)
  
      return None
docs: Tries to find a matcher callable associated to the given alias. If
          an exact match does not exists it will try normalizing it and even
          removing underscores to find one.