code: def TYPE(type_):
          
          if isinstance(type_, symbols.TYPE):
              return type_
  
          assert TYPE.is_valid(type_)
          return gl.SYMBOL_TABLE.basic_types[type_]
docs: Converts a backend type (from api.constants)
          to a SymbolTYPE object (taken from the SYMBOL_TABLE).
          If type_ is already a SymbolTYPE object, nothing
          is done.