prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  There are multiple alembic heads on the develop branch
  The migrations can't be applied on the develop branch because there are multiple alembic heads:
  
  ```
  [vagrant@bodhi-dev bodhi]$ alembic upgrade head
  /usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib64/python2.7/site-packages/zope': missing __init__.py
    file, filename, etc = imp.find_module(subname, path)
  /usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/zope': missing __init__.py
    file, filename, etc = imp.find_module(subname, path)
  /usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/paste': missing __init__.py
    file, filename, etc = imp.find_module(subname, path)
  /usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/moksha': missing __init__.py
    file, filename, etc = imp.find_module(subname, path)
  /usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/repoze': missing __init__.py
    file, filename, etc = imp.find_module(subname, path)
  /home/vagrant/bodhi/bodhi/server/__init__.py:26: DeprecationWarning: unauthenticated_userid: As of Pyramid 1.5 the "pyramid.security.unauthenticated_userid" API is now deprecated.  It will be removed in Pyramd 1.8.  Use the "unauthenticated_userid" attribute of the Pyramid request instead.
    from pyramid.security import unauthenticated_userid
  INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.
  INFO  [alembic.runtime.migration] Will assume transactional DDL.
  ERROR [alembic.util.messaging] Multiple head revisions are present for given argument 'head'; please specify a specific target revision, '<branchname>@head' to narrow to a specific head, or 'heads' for all heads
    FAILED: Multiple head revisions are present for given argument 'head'; please specify a specific target revision,
    '<branchname>@head' to narrow to a specific head, or 'heads' for all heads
  ```
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py`
  Content:
  ```
  1 """Convert the builds table to be polymorphic.
  2 
  3 Revision ID: 9241378c92ab
  4 Revises: fc6b0169c596
  5 Create Date: 2017-04-06 20:37:24.766366
  6 """
  7 from alembic import op
  8 import sqlalchemy as sa
  9 
  10 
  11 # revision identifiers, used by Alembic.
  12 revision = '9241378c92ab'
  13 down_revision = 'fc6b0169c596'
  14 
  15 
  16 def upgrade():
  17     """Add the type column to the builds table."""
  18     # The default of ``1`` is the RPM Build type.
  19     op.add_column('builds', sa.Column('type', sa.Integer(), nullable=False, server_default=u'1'))
  20     op.alter_column('builds', 'type', server_default=None)
  21 
  22 
  23 def downgrade():
  24     """Remove the type column from the builds table."""
  25     op.drop_column('builds', 'type')
  26
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py b/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py
  --- a/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py
  +++ b/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py
  @@ -1,7 +1,7 @@
   """Convert the builds table to be polymorphic.
   
   Revision ID: 9241378c92ab
  -Revises: fc6b0169c596
  +Revises: 12d3e8695f90
   Create Date: 2017-04-06 20:37:24.766366
   """
   from alembic import op
  @@ -10,7 +10,7 @@
   
   # revision identifiers, used by Alembic.
   revision = '9241378c92ab'
  -down_revision = 'fc6b0169c596'
  +down_revision = '12d3e8695f90'
   
   
   def upgrade():
  
verification_info: {"golden_diff": "diff --git a/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py b/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py\n--- a/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py\n+++ b/alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py\n@@ -1,7 +1,7 @@\n \"\"\"Convert the builds table to be polymorphic.\n \n Revision ID: 9241378c92ab\n-Revises: fc6b0169c596\n+Revises: 12d3e8695f90\n Create Date: 2017-04-06 20:37:24.766366\n \"\"\"\n from alembic import op\n@@ -10,7 +10,7 @@\n \n # revision identifiers, used by Alembic.\n revision = '9241378c92ab'\n-down_revision = 'fc6b0169c596'\n+down_revision = '12d3e8695f90'\n \n \n def upgrade():\n", "issue": "There are multiple alembic heads on the develop branch\nThe migrations can't be applied on the develop branch because there are multiple alembic heads:\r\n\r\n```\r\n[vagrant@bodhi-dev bodhi]$ alembic upgrade head\r\n/usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib64/python2.7/site-packages/zope': missing __init__.py\r\n  file, filename, etc = imp.find_module(subname, path)\r\n/usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/zope': missing __init__.py\r\n  file, filename, etc = imp.find_module(subname, path)\r\n/usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/paste': missing __init__.py\r\n  file, filename, etc = imp.find_module(subname, path)\r\n/usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/moksha': missing __init__.py\r\n  file, filename, etc = imp.find_module(subname, path)\r\n/usr/lib64/python2.7/pkgutil.py:186: ImportWarning: Not importing directory '/usr/lib/python2.7/site-packages/repoze': missing __init__.py\r\n  file, filename, etc = imp.find_module(subname, path)\r\n/home/vagrant/bodhi/bodhi/server/__init__.py:26: DeprecationWarning: unauthenticated_userid: As of Pyramid 1.5 the \"pyramid.security.unauthenticated_userid\" API is now deprecated.  It will be removed in Pyramd 1.8.  Use the \"unauthenticated_userid\" attribute of the Pyramid request instead.\r\n  from pyramid.security import unauthenticated_userid\r\nINFO  [alembic.runtime.migration] Context impl PostgresqlImpl.\r\nINFO  [alembic.runtime.migration] Will assume transactional DDL.\r\nERROR [alembic.util.messaging] Multiple head revisions are present for given argument 'head'; please specify a specific target revision, '<branchname>@head' to narrow to a specific head, or 'heads' for all heads\r\n  FAILED: Multiple head revisions are present for given argument 'head'; please specify a specific target revision,\r\n  '<branchname>@head' to narrow to a specific head, or 'heads' for all heads\r\n```\n", "before_files": [{"content": "\"\"\"Convert the builds table to be polymorphic.\n\nRevision ID: 9241378c92ab\nRevises: fc6b0169c596\nCreate Date: 2017-04-06 20:37:24.766366\n\"\"\"\nfrom alembic import op\nimport sqlalchemy as sa\n\n\n# revision identifiers, used by Alembic.\nrevision = '9241378c92ab'\ndown_revision = 'fc6b0169c596'\n\n\ndef upgrade():\n    \"\"\"Add the type column to the builds table.\"\"\"\n    # The default of ``1`` is the RPM Build type.\n    op.add_column('builds', sa.Column('type', sa.Integer(), nullable=False, server_default=u'1'))\n    op.alter_column('builds', 'type', server_default=None)\n\n\ndef downgrade():\n    \"\"\"Remove the type column from the builds table.\"\"\"\n    op.drop_column('builds', 'type')\n", "path": "alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py"}], "after_files": [{"content": "\"\"\"Convert the builds table to be polymorphic.\n\nRevision ID: 9241378c92ab\nRevises: 12d3e8695f90\nCreate Date: 2017-04-06 20:37:24.766366\n\"\"\"\nfrom alembic import op\nimport sqlalchemy as sa\n\n\n# revision identifiers, used by Alembic.\nrevision = '9241378c92ab'\ndown_revision = '12d3e8695f90'\n\n\ndef upgrade():\n    \"\"\"Add the type column to the builds table.\"\"\"\n    # The default of ``1`` is the RPM Build type.\n    op.add_column('builds', sa.Column('type', sa.Integer(), nullable=False, server_default=u'1'))\n    op.alter_column('builds', 'type', server_default=None)\n\n\ndef downgrade():\n    \"\"\"Remove the type column from the builds table.\"\"\"\n    op.drop_column('builds', 'type')\n", "path": "alembic/versions/9241378c92ab_convert_the_builds_table_to_be_.py"}]}