diff --git a/src/drf_yasg/inspectors/view.py b/src/drf_yasg/inspectors/view.py
index 8ad8cc8..52b9319 100644
--- a/src/drf_yasg/inspectors/view.py
+++ b/src/drf_yasg/inspectors/view.py
@@ -8,8 +8,8 @@ from rest_framework.status import is_success
 from .. import openapi
 from ..errors import SwaggerGenerationError
 from ..utils import (
-    force_real_str, force_serializer_instance, get_consumes, get_produces, guess_response_status, is_list_view, no_body,
-    param_list_to_odict
+    force_real_str, force_serializer_instance, get_consumes, get_produces, guess_response_status, is_list_view,
+    merge_params, no_body, param_list_to_odict
 )
 from .base import ViewInspector
 
@@ -162,21 +162,19 @@ class SwaggerAutoSchema(ViewInspector):
         :return: modified parameters
         :rtype: list[openapi.Parameter]
         """
-        parameters = param_list_to_odict(parameters)
         manual_parameters = self.overrides.get('manual_parameters', None) or []
 
         if any(param.in_ == openapi.IN_BODY for param in manual_parameters):  # pragma: no cover
             raise SwaggerGenerationError("specify the body parameter as a Schema or Serializer in request_body")
         if any(param.in_ == openapi.IN_FORM for param in manual_parameters):  # pragma: no cover
-            if any(param.in_ == openapi.IN_BODY for param in parameters.values()):
+            if any(param.in_ == openapi.IN_BODY for param in parameters):
                 raise SwaggerGenerationError("cannot add form parameters when the request has a request body; "
                                              "did you forget to set an appropriate parser class on the view?")
             if self.method not in self.body_methods:
                 raise SwaggerGenerationError("form parameters can only be applied to (" + ','.join(self.body_methods) +
                                              ") HTTP methods")
 
-        parameters.update(param_list_to_odict(manual_parameters))
-        return list(parameters.values())
+        return merge_params(parameters, manual_parameters)
 
     def get_responses(self):
         """Get the possible responses for this view as a swagger :class:`.Responses` object.
diff --git a/src/drf_yasg/openapi.py b/src/drf_yasg/openapi.py
index 8cb50eb..a88da60 100644
--- a/src/drf_yasg/openapi.py
+++ b/src/drf_yasg/openapi.py
@@ -291,6 +291,8 @@ class Paths(SwaggerDict):
 
 
 class PathItem(SwaggerDict):
+    OPERATION_NAMES = ['get', 'put', 'post', 'delete', 'options', 'head', 'patch']
+
     def __init__(self, get=None, put=None, post=None, delete=None, options=None,
                  head=None, patch=None, parameters=None, **extra):
         """Information about a single path
@@ -315,6 +317,15 @@ class PathItem(SwaggerDict):
         self.parameters = filter_none(parameters)
         self._insert_extras__()
 
+    @property
+    def operations(self):
+        """A list of all standard Operations on this PathItem object. See :attr:`.OPERATION_NAMES`.
+
+        :return: list of (method name, Operation) tuples
+        :rtype: list[tuple[str,Operation]]
+        """
+        return [(k, v) for k, v in self.items() if k in PathItem.OPERATION_NAMES and v]
+
 
 class Operation(SwaggerDict):
     def __init__(self, operation_id, responses, parameters=None, consumes=None, produces=None, summary=None,
diff --git a/src/drf_yasg/utils.py b/src/drf_yasg/utils.py
index 472c56d..b14fce8 100644
--- a/src/drf_yasg/utils.py
+++ b/src/drf_yasg/utils.py
@@ -254,6 +254,22 @@ def param_list_to_odict(parameters):
     return result
 
 
+def merge_params(parameters, overrides):
+    """Merge `overrides` into `parameters`. This is the same as appending `overrides` to `parameters`, but any element
+    of `parameters` whose ``(name, in_)`` tuple collides with an element in `overrides` is replaced by it.
+
+    Raises an ``AssertionError`` if either list contains duplicate parameters.
+
+    :param list[.Parameter] parameters: initial parameters
+    :param list[.Parameter] overrides: overriding parameters
+    :return: merged list
+    :rtype: list[.Parameter]
+    """
+    parameters = param_list_to_odict(parameters)
+    parameters.update(param_list_to_odict(overrides))
+    return list(parameters.values())
+
+
 def filter_none(obj):
     """Remove ``None`` values from tuples, lists or dictionaries. Return other objects as-is.