# Concepts and Context Groups (`pydicom.sr`)

The `sr` module contains an interface for DICOM’s CIDs.

`Collection`(name) | Interface for a collection of concepts, such as SNOMED-CT, or a DICOM CID.
`Concepts`(collections) | Management class for the available concept collections.
`Code`(value, scheme_designator, meaning[, ...]) | Namedtuple for representation of a coded concept consisting of the actual code value, the coding scheme designator, the code meaning (and optionally the coding scheme version).

## Usage

Individual `Code` values can be accessed via either their scheme (such as SCT) or the DICOM CID:

    >>> from pydicom.sr import codes
    >>> codes.SCT.Transverse
    Code(value='62824007', scheme_designator='SCT', meaning='Transverse', scheme_version=None)
    >>> codes.CID4.Cornea
    Code(value='28726007', scheme_designator='SCT', meaning='Cornea', scheme_version=None)

A list of available attribute keywords for each scheme or CID is available via `dir()`:

    >>> dir(codes.CID6)
    ['Coronal', 'FiveChamber', 'FourChamber', ... ]