from __future__ import division
from iotbx import shelx, builders

def extract_from(file_name=None, file=None, max_characters=100000):
  # XXX backward compatibility 2009-09-17 - keep max_characters keyword
  assert [file_name, file].count(None) == 1
  stream = shelx.command_stream(file=file, filename=file_name)
  parser = shelx.crystal_symmetry_parser(
    stream, builder=builders.crystal_symmetry_builder())
  parser.parse()
  return parser.builder.crystal_symmetry