Python lexical scanner

[cricket]

i need help with Python lexical scanner for this assignment, i have
create a scanner using the Flex scanner generating tool. The
requirements of the scanner are as follows:

1) Accept input via stdin (standard input).
2) Return output via stdout (standard output)
3) Recognize tokens of the Python programming language
3.1) Tokens are grouped into the following categories:
Newline
Indent
Identifiers
Keywords
Literals
Operators
Delimiters
For INDENT tokens, the format should be

<#> - INDENT - <indent level>
i need help with INDENT,Literals and Newline every time i used \n for
newline it did not work i even used [\n] still did not work.
The scanner should output the tokens discovered in the form:

<#> - <token category> - <token spelling>
for example
10 keyword while or if

Thank you