diff --git a/matplotlibcpp.h b/matplotlibcpp.h
index d95d46ad..dc6100fe 100644
--- a/matplotlibcpp.h
+++ b/matplotlibcpp.h
@@ -435,6 +435,47 @@ PyObject* get_listlist(const std::vector<std::vector<Numeric>>& ll)
 
 } // namespace detail
 
+// helper function to parse keywords dictionary
+static inline std::string trim_copy(const std::string& s) {
+  size_t a = 0, b = s.size();
+  while (a < b && std::isspace(static_cast<unsigned char>(s[a]))) ++a;
+  while (b > a && std::isspace(static_cast<unsigned char>(s[b - 1]))) --b;
+  return s.substr(a, b - a);
+}
+
+static inline PyObject* kw_to_pyobject(const std::string& value_in) {
+  std::string s = trim_copy(value_in);
+  if (s.empty()) return PyUnicode_FromString("");
+
+  // bool / None
+  if (s == "True" || s == "true")  return PyBool_FromLong(1);
+  if (s == "False"|| s == "false") return PyBool_FromLong(0);
+  if (s == "None" || s == "none" || s == "null") { Py_RETURN_NONE; }
+
+  // int
+  {
+    char* end = nullptr;
+    errno = 0;
+    long long iv = std::strtoll(s.c_str(), &end, 10);
+    if (end && *end == '\0' && errno == 0) {
+      return PyLong_FromLong(iv);
+    }
+  }
+
+  // float
+  {
+    char* end = nullptr;
+    errno = 0;
+    double dv = std::strtod(s.c_str(), &end);
+    if (end && *end == '\0' && errno == 0) {
+      return PyFloat_FromDouble(dv);
+    }
+  }
+
+  // fallback: string
+  return PyUnicode_FromString(s.c_str());
+}
+
 /// Plot a line through the given x and y data points..
 ///
 /// See: https://matplotlib.org/3.2.1/api/_as_gen/matplotlib.pyplot.plot.html
@@ -458,7 +499,7 @@ bool plot(const std::vector<Numeric> &x, const std::vector<Numeric> &y, const st
     PyObject* kwargs = PyDict_New();
     for(std::map<std::string, std::string>::const_iterator it = keywords.begin(); it != keywords.end(); ++it)
     {
-        PyDict_SetItemString(kwargs, it->first.c_str(), PyString_FromString(it->second.c_str()));
+        PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
     }
 
     PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_plot, args, kwargs);
@@ -840,7 +881,7 @@ bool fill_between(const std::vector<Numeric>& x, const std::vector<Numeric>& y1,
     // construct keyword args
     PyObject* kwargs = PyDict_New();
     for(std::map<std::string, std::string>::const_iterator it = keywords.begin(); it != keywords.end(); ++it) {
-        PyDict_SetItemString(kwargs, it->first.c_str(), PyUnicode_FromString(it->second.c_str()));
+        PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
     }
 
     PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_fill_between, args, kwargs);
@@ -1959,7 +2000,7 @@ inline void legend(const std::map<std::string, std::string>& keywords)
   PyObject* kwargs = PyDict_New();
   for(std::map<std::string, std::string>::const_iterator it = keywords.begin(); it != keywords.end(); ++it)
   {
-    PyDict_SetItemString(kwargs, it->first.c_str(), PyString_FromString(it->second.c_str()));
+    PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
   }
 
   PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_legend, detail::_interpreter::get().s_python_empty_tuple, kwargs);
@@ -2255,9 +2296,9 @@ inline void subplot(long nrows, long ncols, long plot_number)
 
     // construct positional args
     PyObject* args = PyTuple_New(3);
-    PyTuple_SetItem(args, 0, PyFloat_FromDouble(nrows));
-    PyTuple_SetItem(args, 1, PyFloat_FromDouble(ncols));
-    PyTuple_SetItem(args, 2, PyFloat_FromDouble(plot_number));
+    PyTuple_SetItem(args, 0, PyLong_FromLong(nrows));
+    PyTuple_SetItem(args, 1, PyLong_FromLong(ncols));
+    PyTuple_SetItem(args, 2, PyLong_FromLong(plot_number));
 
     PyObject* res = PyObject_CallObject(detail::_interpreter::get().s_python_function_subplot, args);
     if(!res) throw std::runtime_error("Call to subplot() failed.");
@@ -2303,7 +2344,7 @@ inline void title(const std::string &titlestr, const std::map<std::string, std::
 
     PyObject* kwargs = PyDict_New();
     for (auto it = keywords.begin(); it != keywords.end(); ++it) {
-        PyDict_SetItemString(kwargs, it->first.c_str(), PyUnicode_FromString(it->second.c_str()));
+        PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
     }
 
     PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_title, args, kwargs);
@@ -2438,7 +2479,7 @@ inline void xlabel(const std::string &str, const std::map<std::string, std::stri
 
     PyObject* kwargs = PyDict_New();
     for (auto it = keywords.begin(); it != keywords.end(); ++it) {
-        PyDict_SetItemString(kwargs, it->first.c_str(), PyUnicode_FromString(it->second.c_str()));
+        PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
     }
 
     PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_xlabel, args, kwargs);
@@ -2459,7 +2500,7 @@ inline void ylabel(const std::string &str, const std::map<std::string, std::stri
 
     PyObject* kwargs = PyDict_New();
     for (auto it = keywords.begin(); it != keywords.end(); ++it) {
-        PyDict_SetItemString(kwargs, it->first.c_str(), PyUnicode_FromString(it->second.c_str()));
+        PyDict_SetItemString(kwargs, it->first.c_str(), kw_to_pyobject(it->second.c_str()));
     }
 
     PyObject* res = PyObject_Call(detail::_interpreter::get().s_python_function_ylabel, args, kwargs);