def _most_restrictive(date_elems):
most_index = len(DATE_ELEMENTS)<EOL>for date_elem in date_elems:<EOL><INDENT>if date_elem in DATE_ELEMENTS and DATE_ELEMENTS.index(date_elem) < most_index:<EOL><INDENT>most_index = DATE_ELEMENTS.index(date_elem)<EOL><DEDENT><DEDENT>if most_index < len(DATE_ELEMENTS):<EOL><INDENT>return DATE_ELEMENTS[most_index]<EOL><DEDENT>else:<EOL><INDENT>raise KeyError('<STR_LIT>')<EOL><DEDENT>
Return the date_elem that has the most restrictive range from date_elems