def INDEX_OF_BYTES(string_expression, substring_expression, start=None, end=None):
res = [string_expression, substring_expression]<EOL>if start is not None:<EOL><INDENT>res.append(start)<EOL><DEDENT>if end is not None:<EOL><INDENT>res.append(end)<EOL><DEDENT>return {'<STR_LIT>': res}<EOL>
Searches a string for an occurence of a substring and returns the UTF-8 byte index (zero-based) of the first occurence.
If the substring is not found, returns -1.
https://docs.mongodb.com/manual/reference/operator/aggregation/indexOfBytes/
for more details
:param string_expression: The string or expression of string
:param substring_expression: The string or expression of substring
:param start: An integral number (or expression) that specifies the starting index position for the search.
:param end: An integral number (or expression) that specifies the ending index position for the search.
:return: Aggregation operator