prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Improve toil cluster utils CLI
  Instead of requiring the -p flag make it default to 'aws'. It would also be great to make the cluster name optional -- if the user only has 1 cluster running it should use that by default, else raise an error asking for an explicit argument
  
  </issue>
  <code>
  [start of src/toil/utils/__init__.py]
  1 from __future__ import absolute_import
  2 
  3 from toil import version
  4 import logging
  5 
  6 from toil.provisioners.aws import getCurrentAWSZone
  7 
  8 logger = logging.getLogger( __name__ )
  9 
  10 
  11 def addBasicProvisionerOptions(parser):
  12     parser.add_argument("--version", action='version', version=version)
  13     parser.add_argument('-p', "--provisioner", dest='provisioner', choices=['aws'], required=True,
  14                         help="The provisioner for cluster auto-scaling. Only aws is currently "
  15                              "supported")
  16     currentZone = getCurrentAWSZone()
  17     zoneString = currentZone if currentZone else 'No zone could be determined'
  18     parser.add_argument('-z', '--zone', dest='zone', required=False, default=currentZone,
  19                         help="The AWS availability zone of the master. This parameter can also be "
  20                              "set via the TOIL_AWS_ZONE environment variable, or by the ec2_region_name "
  21                              "parameter in your .boto file, or derived from the instance metadata if "
  22                              "using this utility on an existing EC2 instance. "
  23                              "Currently: %s" % zoneString)
  24     parser.add_argument("clusterName", help="The name that the cluster will be identifiable by. "
  25                                             "Must be lowercase and may not contain the '_' "
  26                                             "character.")
  27     return parser
  28
  [end of src/toil/utils/__init__.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/src/toil/utils/__init__.py b/src/toil/utils/__init__.py
  --- a/src/toil/utils/__init__.py
  +++ b/src/toil/utils/__init__.py
  @@ -5,12 +5,12 @@
   
   from toil.provisioners.aws import getCurrentAWSZone
   
  -logger = logging.getLogger( __name__ )
  +logger = logging.getLogger(__name__)
   
   
   def addBasicProvisionerOptions(parser):
       parser.add_argument("--version", action='version', version=version)
  -    parser.add_argument('-p', "--provisioner", dest='provisioner', choices=['aws'], required=True,
  +    parser.add_argument('-p', "--provisioner", dest='provisioner', choices=['aws'], required=False, default="aws",
                           help="The provisioner for cluster auto-scaling. Only aws is currently "
                                "supported")
       currentZone = getCurrentAWSZone()
  
verification_info: {"golden_diff": "diff --git a/src/toil/utils/__init__.py b/src/toil/utils/__init__.py\n--- a/src/toil/utils/__init__.py\n+++ b/src/toil/utils/__init__.py\n@@ -5,12 +5,12 @@\n \n from toil.provisioners.aws import getCurrentAWSZone\n \n-logger = logging.getLogger( __name__ )\n+logger = logging.getLogger(__name__)\n \n \n def addBasicProvisionerOptions(parser):\n     parser.add_argument(\"--version\", action='version', version=version)\n-    parser.add_argument('-p', \"--provisioner\", dest='provisioner', choices=['aws'], required=True,\n+    parser.add_argument('-p', \"--provisioner\", dest='provisioner', choices=['aws'], required=False, default=\"aws\",\n                         help=\"The provisioner for cluster auto-scaling. Only aws is currently \"\n                              \"supported\")\n     currentZone = getCurrentAWSZone()\n", "issue": "Improve toil cluster utils CLI\nInstead of requiring the -p flag make it default to 'aws'. It would also be great to make the cluster name optional -- if the user only has 1 cluster running it should use that by default, else raise an error asking for an explicit argument\n", "before_files": [{"content": "from __future__ import absolute_import\n\nfrom toil import version\nimport logging\n\nfrom toil.provisioners.aws import getCurrentAWSZone\n\nlogger = logging.getLogger( __name__ )\n\n\ndef addBasicProvisionerOptions(parser):\n    parser.add_argument(\"--version\", action='version', version=version)\n    parser.add_argument('-p', \"--provisioner\", dest='provisioner', choices=['aws'], required=True,\n                        help=\"The provisioner for cluster auto-scaling. Only aws is currently \"\n                             \"supported\")\n    currentZone = getCurrentAWSZone()\n    zoneString = currentZone if currentZone else 'No zone could be determined'\n    parser.add_argument('-z', '--zone', dest='zone', required=False, default=currentZone,\n                        help=\"The AWS availability zone of the master. This parameter can also be \"\n                             \"set via the TOIL_AWS_ZONE environment variable, or by the ec2_region_name \"\n                             \"parameter in your .boto file, or derived from the instance metadata if \"\n                             \"using this utility on an existing EC2 instance. \"\n                             \"Currently: %s\" % zoneString)\n    parser.add_argument(\"clusterName\", help=\"The name that the cluster will be identifiable by. \"\n                                            \"Must be lowercase and may not contain the '_' \"\n                                            \"character.\")\n    return parser\n", "path": "src/toil/utils/__init__.py"}]}