Home › Problems › Inconsistent indentation
Inconsistent indentation
🐛 Fix the bug Topic: functions Difficulty: easy Free
What this problem practises
Function bugs are mostly about names and values: positional argument order, default parameters evaluated once at definition time, local versus global scope, and the implicit None returned whenever a function has no return.
This is a fix-the-bug problem: a short program is given in its broken state, and the task is to repair the code so it produces the required output. The interactive editor runs your fixed version in the browser and checks it for you — no setup, no local interpreter.
Difficulty: easy — the fix or the trick is normally a single line, and a careful read should be enough.
The challenge
This should print a greeting, but won't even run. Fix the indentation.
The code runs in PyDebug’s in-browser compiler. Open the problem, run the snippet, watch the exact error or output, and keep iterating until it is right. Signed-in solves count toward XP and your daily streak.
The error it raises
Run the broken snippet and Python stops with this exact error: IndentationError: unexpected indent. Match it to the Python errors guide, then repair the line that produced it — knowing the message is half the fix.
The snippet
The interactive editor pre-fills exactly this code, broken and ready to repair:
def greet():
print("Hello")
print("Welcome")
greet()Understand the rule
Python uses indentation as syntax. A block must start at one consistent indentation level, and tabs mixed with spaces can look aligned in an editor while representing different characters to the interpreter.
How to trace it
- Locate the line reported by the parser, then inspect the previous block-opening line as well.
- Compare the leading whitespace of sibling statements byte for byte.
- Configure the editor to insert spaces and reveal invisible characters.
- Keep every statement in the same block at the same indentation level.
Common wrong fixes
- Indenting a line because it looks nested even though no colon opened a block.
- Using a tab for one line and four spaces for another.
- Fixing only the reported line while a second sibling line remains misaligned.
Rule to remember
Indentation is part of Python's grammar. Standardise on four spaces, format the whole block, and read the nearest colon before changing whitespace.
🐍 Learning path: Python Basics
Problem 3 of 12 in this path. Work them in order — each one builds on the rule before it.
← Missing indentation after ifNext in path: Missing Colon in for Loop →
More functions problems
Keep going
- Python debugging guide — a systematic method for finding bugs like this one fast.
- Browse every functions problem in this topic.
- Common Python errors and what they actually mean, plus the Python glossary for any term used on this page.