# How to add a custom syspath for Python

When importing libraries, Python will check in the sys.path to know which
subdirectories might contain a package. It will mark any directory containing a
`__init__.py` file as a package or subpackage if its parent also has one.

In order to create a package you then simply have to a have a structure like:

```
sound/                          Top-level package
      __init__.py               Initialize the sound package
      formats/                  Subpackage for file format conversions
              __init__.py
              wavread.py
              wavwrite.py
              aiffread.py
              aiffwrite.py
              auread.py
              auwrite.py
              ...
      effects/                  Subpackage for sound effects
              __init__.py
              echo.py
              surround.py
              reverse.py
              ...
      filters/                  Subpackage for filters
              __init__.py
              equalizer.py
              vocoder.py
              karaoke.py
              ...
```

And to be able to import this package from anywhere you can simply add the
absolute path to `sound` to your syspath before importing it.

## Method 1

```python
import sys
import os

# if you maximum priority you can add it first
sys.path.insert(0, os.path.abspath('/path/to/your/package/'))

# of add it at the end if you does not want priority
sys.path.append(os.path.abspath('/path/to/your/package/'))
```

## Method 2

You can use the `PYTHONPATH` env variable to add new paths to your syspath like
so:
```shell
$ PYTHONPATH="/path/to/your/package/" python3
```