Tracer#

`Galaxy`	Class representing a galaxy, which is composed of attributes used for fitting galaxies (e.g.
`Plane`	A plane of galaxies where all galaxies are at the same redshift.
`Tracer`	Ray-tracer for a lens system with any number of planes.
`SettingsLens`

To treat the redshift of a galaxy as a free parameter in a model, the Redshift object must be used.

This is because PyAutoFit (which handles model-fitting), requires all parameters to be a Python class.

The Redshift object does not need to be used for general PyAutoGalaxy use.

Class used when assigning a redshift to a Galaxy object.