Storage: Handle Existing and New Files

[sanssecours]

Description

In the moment Storage only creates new HDF files. Ideally it should also be possible to handle already existing files, for example to calculate the dataloss of an existing measurement file.

Implementation

After we separate the storage class from the context manager (#55) it might make sense to create a new open_storage method in the (separated) context manager. Here it should be possible to either

• provide a description of the expected measurement data (in case of a new file) or
• call this method “without arguments” to read an already existing measurement file.