β-strand extract scripts

[noobnewcomer]

The paper on Nature:
"""
β-Strand seed library generation
To collect β-strand motifs, a snapshot of the non-redundant set of the PDB was preprocessed with the MASTER softwareto enable fast structural matches. Two template motifs, one consisting of two β-strands and one consisting of three β-strands, were deprived of loops and served as input to MASTER to find sets of structurally similar motifs that would ultimately become the motif dataset for MaSIF.
"""
How can i do this in this repository? I find the script only that extract helix from PDB database.