title: Alembic. ModuleNotFoundError in env.py
body: <p>I have the following project structure</p>
  <pre><code> --some db:
          --some db:
              --alchemy:
                  -- __init__.py
              --alembic:
                  -- versions
                  -- env.py
                  -- README.py
                  -- script.py
              --migrations:
                  -- __init__.py
              --models:
                  -- model_1
                  -- model_2
                  -- __init__.py
  </code></pre>
  <p>I try to autogenerate migrations by alembic.</p>
  <p>I have <code>Base</code> in <code>__init__.py</code> in models folder</p>
  <pre><code>import sqlalchemy as sa
  
  from sqlalchemy.orm import relationship
  from sqlalchemy.ext.declarative import declarative_base, declared_attr
  
  
  metadata = sa.MetaData()
  Base = declarative_base(metadata=metadata)
  </code></pre>
  <p>And import this is env.py</p>
  <pre><code>from logging.config import fileConfig
  
  from alembic import context
  from sqlalchemy import engine_from_config
  from sqlalchemy import pool
  from models import Base
  
  config = context.config
  fileConfig(config.config_file_name)
  target_metadata = Base.metadata
  </code></pre>
  <p>So, when I import Base from models in env.py in alembic directory and try to generate automigration I have some error like</p>
  <blockquote>
  <p>ModuleNotFoundError: No module named 'models'</p>
  </blockquote>
  <p>How can I fix this error?</p>