diff --git a/drees.py b/drees.py
index 53bba28..7354659 100644
--- a/drees.py
+++ b/drees.py
@@ -104,7 +104,7 @@ def get_enum_field(value):
             return field.value
 
 
-def group_by_age_date(data: Dict[str, Any], fields: List[str]) -> Dict[dt, Any]:
+def group_by_age_date(data: Dict[str, Any]) -> Dict[dt, Any]:
     """
     group the original dictionnary into a more readable one
     'date': {
@@ -131,8 +131,10 @@ def group_by_age_date(data: Dict[str, Any], fields: List[str]) -> Dict[dt, Any]:
             dic_data_grouped[date][age] = OrderedDict()
         if vac_status not in dic_data_grouped[date][age]:
             dic_data_grouped[date][age][vac_status] = OrderedDict()
-        for field in fields:
-            dic_data_grouped[date][age][vac_status][field] = row_fields[field]
+        for field in Field:
+            dic_data_grouped[date][age][vac_status][field.label] = row_fields[
+                field.label
+            ]
     logging.info("data restructured")
     return dic_data_grouped
 
@@ -209,8 +211,8 @@ def plot_cumulative_field(
         np_cumulate_unvac: np.ndarray = np.cumsum(
             np_data_unvac[:, age_group.value, field.value], axis=0
         )
-        plt.plot(np_date, np_cumulate_vac, label=f"{age_group.label} vaccinate")
-        plt.plot(np_date, np_cumulate_unvac, label=f"{age_group.label} unvaccinate")
+        plt.plot(np_date, np_cumulate_vac, label=f"{age_group.label} vax")
+        plt.plot(np_date, np_cumulate_unvac, label=f"{age_group.label} no vax")
 
     plt.title(f"nombre de {field.label} cumulé par age")
     plt.xlabel("date")
@@ -266,6 +268,7 @@ def plot_bar_data_by_age_field(
     a limit days period is set to have an readable plot
     """
     np_percent_vac, np_percent_unvac = get_vaccine_percent(np_data)
+    # adjust the fig size to display correctly bars and labels
     fig, ax = get_plot_fig(figsize=(22, 8))
 
     for idx_date in range(len(np_date)):
@@ -275,15 +278,15 @@ def plot_bar_data_by_age_field(
         unvac_percent = np.round(
             np_percent_unvac[idx_date, age_group.value, field.value] * 100
         )
-        bar_vac = ax.bar(idx_date, vac_percent, color="b", label="vac")
-        bar_unvac = ax.bar(
-            idx_date, unvac_percent, bottom=vac_percent, color="r", label="novac"
-        )
+        bar_vac = ax.bar(idx_date, vac_percent, color="b", label="vax")
+        ax.bar(idx_date, unvac_percent, bottom=vac_percent, color="r", label="no vax")
         ax.bar_label(bar_vac, label_type="edge", color="black", fontsize="8")
-        ax.set_ylim(top=105)
+        ax.set_ylim(top=105)  # to display 100% label
 
     ax.set_ylabel("%")
     ax.set_title(f"{age_group.label} - {field.label}")
+
+    # avoid displaying all dates
     ax.set(
         xticks=range(len(np_date)),
         xticklabels=[
@@ -291,7 +294,7 @@ def plot_bar_data_by_age_field(
             for idx, d in enumerate(np_date.astype(dt))
         ],
     )
-    plt.legend(["vaccinate", "unvaccinate"], loc=0, frameon=True)
+    plt.legend(["vax", "no vax"], loc=0, frameon=True)
 
     save_and_close_fig(
         fig,
@@ -351,9 +354,7 @@ if __name__ == "__main__":
     dic_data: Dict[str, Any] = get_data(
         file_path=os.path.join(DATA_REPOSITORY, "dress.json"), refresh=args.refresh
     )
-    dic_data_grouped: Dict[dt, Any] = group_by_age_date(
-        dic_data, [x.label for x in Field]
-    )
+    dic_data_grouped: Dict[dt, Any] = group_by_age_date(dic_data)
 
     np_data, np_date = get_np_data(dic_data_grouped)
 
diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 0000000..e6d02cc
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,4 @@
+[mypy]
+python_version = 3.8
+ignore_missing_imports = True
+disable_error_code = attr-defined
\ No newline at end of file
diff --git a/requirements.txt b/requirements.txt
index fa28a2f..2bf0bf6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,16 +5,22 @@ chardet==4.0.0
 click==8.0.1
 cycler==0.10.0
 idna==2.10
+isort==5.10.1
 kiwisolver==1.3.1
 matplotlib==3.4.2
+mypy==0.920
 mypy-extensions==0.4.3
 numpy==1.20.3
 pathspec==0.8.1
 Pillow==8.2.0
 pyparsing==2.4.7
 python-dateutil==2.8.1
+pytz==2021.3
 regex==2021.4.4
 requests==2.25.1
 six==1.16.0
 toml==0.10.2
+tomli==2.0.0
+types-requests==2.26.2
+typing-extensions==4.0.1
 urllib3==1.26.4