converted to python3

[OliPelz]

Adapted script to make it compatible with python3:

• String Comparison: Changed basestring to str.
• Iterator Protocol: Removed the usage of StopIteration and ensured the iterator ends without explicit raise StopIteration.
• Print Statement: Changed print to sys.stdout.write for the final output to avoid the trailing newline
• hebang Line: Updated to #!/usr/bin/python3 to specify Python 3 interpreter.
• all tests did pass

t10.sh passed
t2.sh passed
t3.sh passed
t5.sh passed
t7.sh passed
t9.sh passed
t_arithmetic_expansion.sh passed
t_case.sh passed
t_dot.sh passed
t_escaped.sh passed
t_functions.sh passed
t_heredocs_and_herestrings.sh passed
t_if_statement.sh passed
t_line_continuation.sh passed
t_parameters_expansion.sh passed
t_pipe.sh passed
t_process_substitution.sh passed
t_while_until_loops.sh passed
PASSED 18, FAILED 0