def __init__(self, lines):

self._lines = lines

self.line_numbers_with_nodes = set()

self.line_numbers_with_statements = []

def generic_visit(self, node):

if hasattr(node, 'col_offset') and hasattr(node, 'lineno') and node.col_offset == 0:

self.line_numbers_with_nodes.add(node.lineno)

if isinstance(node, ast.stmt):

self.line_numbers_with_statements.append(node.lineno)

"""Tokenize Python source code."""

# Using an undocumented API as the documented one in Python 2.7 does not work as needed

# cross-version.

if sys.version_info < (3,) and isinstance(source, str):

source = source.decode()

"""Return a list of all global statement blocks.

tree = ast.parse(source)

visitor = Visitor(lines)

visitor.visit(tree)

statement_ranges = []

for index, line_number in enumerate(visitor.line_numbers_with_statements):

remaining_line_numbers = visitor.line_numbers_with_statements[index+1:]

end_line_number = len(lines) if len(remaining_line_numbers) == 0 else min(remaining_line_numbers) - 1

current_statement_is_oneline = line_number == end_line_number

if len(statement_ranges) == 0:

statement_ranges.append((line_number, end_line_number, current_statement_is_oneline))

continue

previous_statement = statement_ranges[-1]

previous_statement_is_oneline = previous_statement[2]

if previous_statement_is_oneline and current_statement_is_oneline:

statement_ranges[-1] = previous_statement[0], end_line_number, True

else:

statement_ranges.append((line_number, end_line_number, current_statement_is_oneline))

"""Normalize blank lines for sending to the terminal.

lines = source.splitlines(False)

# If we have two blank lines, then add two blank lines.

# Do not trim the spaces, if we have blank lines with spaces, its possible

# we have indented code.

if (len(lines) > 1 and len(''.join(lines[-2:])) == 0) \

or source.endswith(('\n\n', '\r\n\r\n')):

trailing_newline = '\n' * 2

# Find out if we have any trailing blank lines

elif len(lines[-1].strip()) == 0 or source.endswith(('\n', '\r\n')):

trailing_newline = '\n'

else:

trailing_newline = ''

# Step 1: Remove empty lines.

tokens = _tokenize(source)

newlines_indexes_to_remove = (spos[0] for (toknum, tokval, spos, epos, line) in tokens

if len(line.strip()) == 0

and token.tok_name[toknum] == 'NL'

and spos[0] == epos[0])

for line_number in reversed(list(newlines_indexes_to_remove)):

del lines[line_number-1]

# Step 2: Add blank lines between each global statement block.

# A consequtive single lines blocks of code will be treated as a single statement,

# just to ensure we do not unnecessarily add too many blank lines.

source = '\n'.join(lines)

tokens = _tokenize(source)

dedent_indexes = (spos[0] for (toknum, tokval, spos, epos, line) in tokens

if toknum == token.DEDENT and _indent_size(line) == 0)

global_statement_ranges = _get_global_statement_blocks(source, lines)

start_positions = map(operator.itemgetter(0), reversed(global_statement_ranges))

for line_number in filter(lambda x: x > 1, start_positions):

lines.insert(line_number-1, '')

sys.stdout.write('\n'.join(lines) + trailing_newline)