def _is_derived(i):
for lookup_range in _nr_prefix_strings.keys():<EOL><INDENT>if i in lookup_range:<EOL><INDENT>return True<EOL><DEDENT><DEDENT>return False<EOL>
Helper function for determining if a Unicode scalar value falls into one of the ranges of derived names.

:param i: Unicode scalar value.
:return: Boolean.  True if the value is in one of the derived ranges.  False otherwise.