diff --git a/semeio/workflows/localisation/local_config_script.py b/semeio/workflows/localisation/local_config_script.py
index bd0095cef..8a86e5e43 100644
--- a/semeio/workflows/localisation/local_config_script.py
+++ b/semeio/workflows/localisation/local_config_script.py
@@ -195,6 +195,51 @@ def run(self, *args):
           scalingfactors: [1.0, 0.5, 0.3]
           smooth_ranges: [2,3]
 
+Example 2:
+------------
+In this example the optional keyword **max_gen_obs_size** is specified.
+The value 1000 means that all observation nodes of type GEN_OBS having less
+than 1000 observations are specified in the form::
+
+ nodename:index
+
+where **index** is an integer from 0 to 999.
+All GEN_OBS nodes with more than 1000 observations
+are specified in the form nodename only. The reason not to enable to specify
+individual observations from GEN_OBS of any size is performance e.g. when
+GEN_OBS nodes of seismic data is used.
+
+The first example below (2A) specifies all observations by::
+
+ GENOBS_NODE:*
+
+The second example (2B) has selected a few observations from the
+GENOBS_NODE::
+
+  ["GENOBS_NODE:0","GENOBS_NODE:3","GENOBS_NODE:55"]
+
+Example 2A::
+
+  max_gen_obs_size: 1000
+  log_level:2
+  correlations:
+    - name: CORR1
+       obs_group:
+          add: ["GENOBS_NODE:*"]
+       param_group:
+          add: ["PARAM_NODE:*"]
+
+Example 2B::
+
+  max_gen_obs_size: 100
+  log_level:2
+  correlations:
+    - name: CORR1
+       obs_group:
+          add: ["GENOBS_NODE:0","GENOBS_NODE:3","GENOBS_NODE:55"]
+       param_group:
+          add: ["PARAM_NODE:*"]
+
 
 Keywords
 -----------
@@ -212,6 +257,16 @@ def run(self, *args):
       and make it possible to visualise them. Is only relevant when using
       **field_scale** with methods calculating the scaling factors.
 
+:max_gen_obs_size:
+      Specify the max size of GEN_OBS type of observation nodes that
+      can specify individual observations. Individual observations are specified
+      by nodename:index where index is the observation number in the
+      observation file associated with the GEN_OBS type node.
+      The keyword is optional. If not specified or specified with value 0,
+      this means that observations of type GEN_OBS is specified by
+      nodename only. Individual observations can not be specified in this case
+      which means that all observations in the GEN_OBS node is used.
+
 :correlations:
       List of specifications of correlation groups. A correlation group
       specify a set of observations and a set of model parameters.
@@ -296,6 +351,13 @@ def run(self, *args):
       The nodename represents all field values for all grid cells in the whole
       3D or 2D grid the field belongs to.
 
+      For observations specified with GENERAL_OBSERVATION keyword in ERT config file,
+      it is possible to specify the observations by either *node_name*
+      or *node_name:index*. Default is to specify by *node_name* only which means
+      to include all observation from this ERT identifier.
+      The alternative option is to use the keyword **max_gen_obs_size**
+      described above and specify individual observations by *node_name:index*.
+
 :remove:
       For details see the keyword **add:**. The main purpose of **remove** is to
       have a quick and easy way to specify all parameters or observations
diff --git a/tests/legacy_test_data/poly_gen_param/poly_eval.py b/tests/legacy_test_data/poly_gen_param/poly_eval.py
index 5ed27038d..251a63a6c 100755
--- a/tests/legacy_test_data/poly_gen_param/poly_eval.py
+++ b/tests/legacy_test_data/poly_gen_param/poly_eval.py
@@ -9,7 +9,7 @@ def _load_coeffs(filename):
 
 
 def _evaluate(coeffs, x):
-    return coeffs["a"] * x ** 2 + coeffs["b"] * x + coeffs["c"]
+    return coeffs["a"] * x**2 + coeffs["b"] * x + coeffs["c"]
 
 
 if __name__ == "__main__":