text: import argparse
  import codecs
  import sys
  import json
  
  from sqlalchemy.engine import create_engine
  from sqlalchemy.schema import MetaData
  import pkg_resources
  
  from sqlacodegen.codegen import CodeGenerator
  from sqlalchemy_utils.types.ltree import LtreeType
  from sqlalchemy.dialects.postgresql.base import ischema_names
  
  ischema_names['ltree'] = LtreeType
  
  def main():
      parser = argparse.ArgumentParser(description='Generates SQLAlchemy model code from an existing database.')
      parser.add_argument('url', nargs='?', help='SQLAlchemy url to the database')
      parser.add_argument('--version', action='store_true', help="print the version number and exit")
      parser.add_argument('--schema', help='load tables from an alternate schema')
      parser.add_argument('--tables', help='tables to process (comma-separated, default: all)')
      parser.add_argument('--noviews', action='store_true', help="ignore views")
      parser.add_argument('--noindexes', action='store_true', help='ignore indexes')
      parser.add_argument('--noconstraints', action='store_true', help='ignore constraints')
      parser.add_argument('--nojoined', action='store_true', help="don't autodetect joined table inheritance")
      parser.add_argument('--noinflect', action='store_true', help="don't try to convert tables names to singular form")
      parser.add_argument('--noclasses', action='store_true', help="don't generate classes, only tables")
      parser.add_argument('--outfile', help='file to write output to (default: stdout)')
      parser.add_argument('--audited', help='comma separated list of audited table names')
      parser.add_argument('--auditall', action='store_true', help='audit all tables')
      parser.add_argument('--relationship', action='append', nargs=4, metavar=('parent', 'child', 'name', 'kwargs'), help='Creates an association with the specified name')
      parser.add_argument('--loginuser', help='Model name that will instantiate the flask-login "UserMixin" (default: none)')
      parser.add_argument('--loginrole', help='Model name that will instantiate the flask-login "UserRole" (default: none)')
      args = parser.parse_args()
  
      if args.version:
          version = pkg_resources.get_distribution('sqlacodegen').parsed_version
          print(version.public)
          return
      if not args.url:
          print('You must supply a url\n', file=sys.stderr)
          parser.print_help()
          return
      _relationship = dict()
      _rel_set = set()
      args.relationship = [] if args.relationship is None else args.relationship
      for (key, child, name, kwargs) in args.relationship:
          val = { 'child' : child,
                  'name' : name,
                  'kwargs' : json.loads(kwargs)
                }
          if not (key in _relationship):
              _relationship[key] = []
          # There must not be conflicts where a table is given
          # forced relationships that share an an attribute name
          if (key, name) in _rel_set:
              raise KeyError(f'Tried to create a forced relationship "{name}" '
                             +f'within {key}, but another forced relationship '
                             +f'exists in {key} with the same name.')
          _rel_set.add((key, name))
  
          _relationship[key].append(val)
      args.relationship = _relationship
      engine = create_engine(args.url)
      metadata = MetaData(engine)
      tables = args.tables.split(',') if args.tables else None
      metadata.reflect(engine, args.schema, not args.noviews, tables)
      outfile = codecs.open(args.outfile, 'w', encoding='utf-8') if args.outfile else sys.stdout
  
      if args.audited:
          args.audited = set(args.audited.split(','))
  
      generator = CodeGenerator(metadata,
                                args.noindexes,
                                args.noconstraints,
                                args.nojoined,
                                args.noinflect,
                                args.noclasses,
                                audited=args.audited,
                                audit_all=args.auditall,
                                flask_login_user=args.loginuser,
                                flask_login_role=args.loginrole,
                                force_relationship=args.relationship)
      generator.render(outfile)
  