diff --git a/src/PYTHON/python_impl.cpp b/src/PYTHON/python_impl.cpp
index 556a79261a..483038cc1c 100644
--- a/src/PYTHON/python_impl.cpp
+++ b/src/PYTHON/python_impl.cpp
@@ -451,16 +451,23 @@ int PythonImpl::find(const char *name)
    ensure a string is returned only if retrieve() is the caller
 --------------------------------------------------------------------- */
 
-int PythonImpl::function_match(const char *name, const char *varname, int numeric)
+int PythonImpl::function_match(const char *name, const char *varname, int numeric, Error *error)
 {
-  // NOTE to Richard - any reason not to put error messages here instead of in Variable class ?
-  //   error messages appear 3x in Variable
-
   int ifunc = find(name);
-  if (ifunc < 0) return -1;
-  if (pfuncs[ifunc].noutput == 0) return -2;
-  if (strcmp(pfuncs[ifunc].ovarname, varname) != 0) return -3;
-  if (numeric && pfuncs[ifunc].otype == STRING) return -4;
+
+  if (ifunc < 0)
+    error->all(FLERR, Error::NOLASTLINE, "Python function {} specified by variable {} not found",
+               name, varname);
+  if (pfuncs[ifunc].noutput == 0)
+    error->all(FLERR, Error::NOLASTLINE,
+               "Python function {} for variable {} does not return a value", name, varname);
+  if (strcmp(pfuncs[ifunc].ovarname, varname) != 0)
+    error->all(FLERR, Error::NOLASTLINE,
+               "Python function {} and variable {} do not not link to each other", name, varname);
+  if (numeric && pfuncs[ifunc].otype == STRING)
+    error->all(FLERR, Error::NOLASTLINE, "Python function {} for variable {} returns a string",
+               name, varname);
+
   return ifunc;
 }
 
@@ -477,18 +484,18 @@ int PythonImpl::function_match(const char *name, const char *varname, int numeri
      other classes avoid this issue by setting variable indices in their init() method
 --------------------------------------------------------------------- */
 
-int PythonImpl::wrapper_match(const char *name, const char *varname, int narg, int *argvars)
+int PythonImpl::wrapper_match(const char *name, const char *varname, int narg, int *argvars,
+                              Error *error)
 {
-  // NOTE to Richard - any reason not to put 2 extra error messages here instead of in Variable class ?
-  //   only this class knows the name of the missing internal var, so can generate better error message
-
-  int ifunc = function_match(name, varname, 1);
+  int ifunc = function_match(name, varname, 1, error);
   if (ifunc < 0) return ifunc;
 
   int internal_count = 0;
   for (int i = 0; i < pfuncs[ifunc].ninput; i++)
     if (pfuncs[ifunc].ivarflag[i] == INTERNALVAR) internal_count++;
-  if (internal_count != narg) return -5;
+  if (internal_count != narg)
+    error->all(FLERR, Error::NOLASTLINE,
+               "Python function {} does not use {} internal variable args", name, narg);
 
   // set argvars of internal-style variables for use by Variable class
   //   in Python wrapper functions
@@ -496,13 +503,15 @@ int PythonImpl::wrapper_match(const char *name, const char *varname, int narg, i
   //   so that invoke_function() is as fast as possible for args which are internal-style vars
 
   int j = 0;
-  for (int i = 0; i < pfuncs[ifunc].ninput; i++)
+  for (int i = 0; i < pfuncs[ifunc].ninput; i++) {
     if (pfuncs[ifunc].ivarflag[i] == INTERNALVAR) {
       int ivar = input->variable->find(pfuncs[ifunc].svalue[i]);
-      if (ivar < 0) return -6;
+      error->all(FLERR, Error::NOLASTLINE, "Python function {} cannot find internal variable {}",
+                 name, pfuncs[ifunc].svalue[i]);
       pfuncs[ifunc].internal_var[i] = ivar;
       argvars[j++] = ivar;
     }
+  }
 
   return ifunc;
 }
diff --git a/src/PYTHON/python_impl.h b/src/PYTHON/python_impl.h
index 3ead92f6f2..5c3955afc6 100644
--- a/src/PYTHON/python_impl.h
+++ b/src/PYTHON/python_impl.h
@@ -27,8 +27,8 @@ class PythonImpl : protected Pointers, public PythonInterface {
   void command(int, char **) override;
   void invoke_function(int, char *, double *) override;
   int find(const char *) override;
-  int function_match(const char *, const char *, int) override;
-  int wrapper_match(const char *, const char *, int, int *) override;
+  int function_match(const char *, const char *, int, Error *) override;
+  int wrapper_match(const char *, const char *, int, int *, Error *) override;
   char *long_string(int) override;
   int execute_string(char *) override;
   int execute_file(char *) override;
diff --git a/src/lmppython.cpp b/src/lmppython.cpp
index 6a8bc1f5a2..f7a213302a 100644
--- a/src/lmppython.cpp
+++ b/src/lmppython.cpp
@@ -14,9 +14,8 @@
 #include "lmppython.h"
 #if defined(LMP_PYTHON)
 #include "python_impl.h"
-#else
-#include "error.h"
 #endif
+#include "error.h"
 
 using namespace LAMMPS_NS;
 
@@ -43,7 +42,7 @@ void Python::init()
 #if defined(LMP_PYTHON)
   if (!impl) impl = new PythonImpl(lmp);
 #else
-  error->all(FLERR, "Python support missing! Compile with PYTHON package installed!");
+  error->all(FLERR, Error::NOLASTLINE, "Python support missing! Compile with PYTHON package installed!");
 #endif
 }
 
@@ -83,19 +82,19 @@ int Python::find(const char *name)
 
 /* ------------------------------------------------------------------ */
 
-int Python::function_match(const char *name, const char *varname, int numeric)
+int Python::function_match(const char *name, const char *varname, int numeric, Error *errptr)
 {
   init();
-  return impl->function_match(name, varname, numeric);
+  return impl->function_match(name, varname, numeric, errptr);
 }
 
 /* ------------------------------------------------------------------ */
 
-int Python::wrapper_match(const char *name, const char *varname,
-                          int narg, int *argvars)
+int Python::wrapper_match(const char *name, const char *varname, int narg, int *argvars,
+                          Error *errptr)
 {
   init();
-  return impl->wrapper_match(name, varname, narg, argvars);
+  return impl->wrapper_match(name, varname, narg, argvars, errptr);
 }
 
 /* ------------------------------------------------------------------ */
diff --git a/src/lmppython.h b/src/lmppython.h
index 23137b7ecb..f7db8a4c06 100644
--- a/src/lmppython.h
+++ b/src/lmppython.h
@@ -24,8 +24,8 @@ class PythonInterface {
   virtual void command(int, char **) = 0;
   virtual void invoke_function(int, char *, double *) = 0;
   virtual int find(const char *) = 0;
-  virtual int function_match(const char *, const char *, int) = 0;
-  virtual int wrapper_match(const char *, const char *, int, int *) = 0;
+  virtual int function_match(const char *, const char *, int, Error *) = 0;
+  virtual int wrapper_match(const char *, const char *, int, int *, Error *) = 0;
   virtual char *long_string(int ifunc) = 0;
   virtual int execute_string(char *) = 0;
   virtual int execute_file(char *) = 0;
@@ -40,8 +40,8 @@ class Python : protected Pointers {
   void command(int, char **);
   void invoke_function(int, char *, double *);
   int find(const char *);
-  int function_match(const char *, const char *, int);
-  int wrapper_match(const char *, const char *, int, int *);
+  int function_match(const char *, const char *, int, Error *);
+  int wrapper_match(const char *, const char *, int, int *, Error *);
   char *long_string(int ifunc);
   int execute_string(char *);
   int execute_file(char *);
diff --git a/src/variable.cpp b/src/variable.cpp
index 07f331c72a..5f848913c8 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -959,31 +959,10 @@ void Variable::python_command(int narg, char **arg)
 
 int Variable::equalstyle(int ivar)
 {
-  if (style[ivar] == EQUAL || style[ivar] == TIMER ||
-      style[ivar] == INTERNAL) return 1;
-  if (style[ivar] == PYTHON) {
-    pyindex[ivar] = python->function_match(data[ivar][0],names[ivar],1);
-    if (pyindex[ivar] < 0) {
-      int ierror = pyindex[ivar];
-      if (ierror == -1) {
-        error->all(FLERR, "Python function {} specified by variable {} not found",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -2) {
-        error->all(FLERR, "Python function {} for variable {} does not return a value",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -3) {
-        error->all(FLERR, "Python function {} and variable {} do not not link to each other",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -4) {
-        error->all(FLERR, "Python function {} for variable {} returns a string",
-                   data[ivar][0], names[ivar]);
-      } else {
-        error->all(FLERR, "Unknown error linking Python function {} to variable {}",
-                   data[ivar][0],names[ivar]);
-      }
-      return 0;
-    } else return 1;
-  }
+  if (style[ivar] == EQUAL || style[ivar] == TIMER || style[ivar] == INTERNAL) return 1;
+  if ((style[ivar] == PYTHON) && (python->function_match(data[ivar][0], names[ivar], 1, error) >= 0))
+    return 1;
+
   return 0;
 }
 
@@ -1103,22 +1082,7 @@ char *Variable::retrieve(const char *name)
     str = data[ivar][1] = utils::strdup(result);
 
   } else if (style[ivar] == PYTHON) {
-    int ifunc = python->function_match(data[ivar][0],name,0);
-    if (ifunc < 0) {
-      if (ifunc == -1) {
-        error->all(FLERR, "Python function {} specified by variable {} not found",
-                   data[ivar][0], name);
-      } else if (ifunc == -2) {
-        error->all(FLERR, "Python function {} for variable {} does not return a value",
-                   data[ivar][0], name);
-      } else if (ifunc == -3) {
-        error->all(FLERR, "Python function {} and variable {} do not not link to each other",
-                   data[ivar][0], name);
-      } else {
-        error->all(FLERR, "Unknown error linking Python function {} to variable {}",
-                   data[ivar][0],name);
-      }
-    }
+    int ifunc = python->function_match(data[ivar][0],name,0,error);
     python->invoke_function(ifunc,data[ivar][1],nullptr);
     str = data[ivar][1];
 
@@ -4208,32 +4172,7 @@ int Variable::math_function(char *word, char *contents, Tree **tree, Tree **tree
     // jvars = returned indices of narg internal variables used by Python function
 
     int *jvars = new int[narg];
-    pyindex[pyvar] = python->wrapper_match(data[pyvar][0],names[pyvar],narg,jvars);
-    if (pyindex[pyvar] < 0) {
-      int ierror = pyindex[pyvar];
-      if (ierror == -1) {
-        error->all(FLERR, "Python function {} specified by variable {} not found",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -2) {
-        error->all(FLERR, "Python function {} for variable {} does not return a value",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -3) {
-        error->all(FLERR, "Python function {} and variable {} do not not link to each other",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -4) {
-        error->all(FLERR, "Python function {} for variable {} returns a string",
-                   data[ivar][0], names[ivar]);
-      } else if (ierror == -5) {
-        error->all(FLERR, "Python function {} does not use {} internal variable args",
-                   data[ivar][0], narg);
-      } else if (ierror == -6) {
-        error->all(FLERR,"Python function {} cannot find an internal variable",
-                   data[ivar][0]);
-      } else {
-        error->all(FLERR, "Unknown error linking Python function {} to variable {}",
-                   data[ivar][0],names[ivar]);
-      }
-    }
+    pyindex[pyvar] = python->wrapper_match(data[pyvar][0],names[pyvar],narg,jvars,error);
 
     // if tree: store python variable and arg info in tree for later eval
     // else: one-time eval of python-coded function now via python variable