ImportError: cannot import name

Verify the name exists in the target module and is spelled correctly.

# ❌ Typo
from datetime import datetim  # ImportError

# ✅ Correct
from datetime import datetime

# Check what names a module exports
import datetime
print([x for x in dir(datetime) if not x.startswith("_")])

Restructure code to break circular dependencies.

# ❌ Circular: module_a imports from module_b, module_b imports from module_a

# ✅ Solution 1: Move shared code to a third module
# shared.py: class BaseModel
# module_a.py: from shared import BaseModel
# module_b.py: from shared import BaseModel

# ✅ Solution 2: Lazy import inside a function (defers import until called)
# module_a.py
def get_user():
    from module_b import User  # Import only when function is called
    return User.query.first()

Use python -m to run scripts that use relative imports.

# ❌ Direct execution fails with relative imports
python app/utils/helper.py
# ImportError: attempted relative import with no known parent package

# ✅ Run as module
python -m app.utils.helper

# Project structure:
# app/
#   __init__.py
#   utils/
#     __init__.py
#     helper.py