old_contents: from sqlalchemy import create_engine
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy import Column , Integer, String, Float, Date
  from sqlalchemy.orm import sessionmaker
  
  engine=create_engine("sqlite:///tmp.db")
  #engine=create_engine("sqlite://")
  Base=declarative_base()
  
  class Pyexcel(Base):
      __tablename__='pyexcel'
      id=Column(Integer, primary_key=True)
      name=Column(String)
      weight=Column(Float)
      birth=Column(Date)
  
  class Signature(Base):
      __tablename__="signature"
      X=Column(Integer, primary_key=True)
      Y=Column(Integer)
      Z=Column(Integer)
  
  class Signature2(Base):
      __tablename__="signature2"
      A=Column(Integer, primary_key=True)
      B=Column(Integer)
      C=Column(Integer)
      
  Session=sessionmaker(bind=engine)
  
  
new_contents: from sqlalchemy import create_engine
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy import Column , Integer, String, Float, Date
  from sqlalchemy.orm import sessionmaker
  import platform
  
  engine = None
  if platform.python_implementation() == 'PyPy':
      engine=create_engine("sqlite:///tmp.db")
  else:
      engine=create_engine("sqlite://")
  
  Base=declarative_base()
  
  class Pyexcel(Base):
      __tablename__='pyexcel'
      id=Column(Integer, primary_key=True)
      name=Column(String)
      weight=Column(Float)
      birth=Column(Date)
  
  class Signature(Base):
      __tablename__="signature"
      X=Column(Integer, primary_key=True)
      Y=Column(Integer)
      Z=Column(Integer)
  
  class Signature2(Base):
      __tablename__="signature2"
      A=Column(Integer, primary_key=True)
      B=Column(Integer)
      C=Column(Integer)
      
  Session=sessionmaker(bind=engine)
  
  
subject: Fix #50, come on, use physcial file to avoid definite crash on pypy