diff --git a/pytex/pytex.py b/pytex/pytex.py
index 2ecffab..b0d0295 100644
--- a/pytex/pytex.py
+++ b/pytex/pytex.py
@@ -40,33 +40,51 @@ def update_export_dict(new_dict):
     """
     EXPORT_DICT.update(new_dict)
 
+def run_python(template:str, data:dict):
+    """ Runs python commands using data
+        
+    :param template: string containing python commands
+    :param data: dictionary with variables needed to run commands
 
-def feed(template, data, output="", force=0):
-    """ Feed template with data to output
+    """
+    jinja_template = texenv.from_string(template)
+    return jinja_template.render(**data)
 
-    :param template: jinja2 template with texenv environment
-    :param data: Data dictionnary
+def build_output(filename):
+    """ Replace tpl with a number in filename and insure that this file does not exists """
+
+    num = 1
+    output_p = Path(filename.replace('tpl', f'{num:02d}'))
+    while output_p.exists():
+        logger.debug(f"{output_p} exists. Try next one")
+        num += 1
+        output_p = Path(filename.replace('tpl', f'{num:02d}'))
+
+    return output_p
+
+def feed(template_filename, data, output="", force=0):
+    """ Feed template_filename with data and write it to output
+
+    :param template_filename: jinja2 template with texenv environment
+    :param data: Data dictionary
     :param output: name of the output file
     (by default: tpl is replaced by a 2 digits number)
     :param force: Override is the output already exists
 
-    :return: name of fed template
+    :return: output filename
     """
-    logger.info(f"Getting template {template}")
-    tpl = texenv.get_template(str(template))
+    logger.info(f"Getting template_filename {template_filename}")
+    with open(template_filename, "r") as f:
+        fed = run_python("".join(f.readlines()), data)
 
     if not output:
-        num = 1
-        output_p = Path(template.replace('tpl', f'{num:02d}'))
-        while output_p.exists() and not force:
-            logger.debug(f"{output_p} exists. Try next one")
-            num += 1
-            output_p = Path(template.replace('tpl', f'{num:02d}'))
+        output_p = build_output(template_filename)
     else:
         output_p = Path(output)
-        if not force and output_p.exists():
-            logger.error(f"{output} exists. Use force=1 do override it")
-            raise ValueError(f"{output} exists. Use force=1 do override it")
+
+    if not force and output_p.exists():
+        logger.error(f"{output} exists. Use force=1 do override it")
+        raise ValueError(f"{output} exists. Use force=1 do override it")
 
     output_dir = output_p.parent
     if output_dir and not output_dir.exists():
@@ -74,8 +92,9 @@ def feed(template, data, output="", force=0):
         output_dir.mkdir(exist_ok=True)
 
     with open(output_p, "w") as output_f:
-        output_f.write(tpl.render(**EXPORT_DICT, **data))
-    logger.info(f"{template} has been rendered to {output}.")
+        output_f.write(fed)
+    logger.info(f"{template_filename} has been rendered to {output}.")
+
     return output_p
 
 
@@ -93,7 +112,7 @@ def pdflatex(tex_filename, output_dir=""):
     os.chdir(output_dir)
     compilation = subprocess.Popen(
         [
-            "pdflatex",
+            "lualatex",
             f"-output-directory={output_dir}",
             # "-halt-on-error",
             "-interaction=nonstopmode",
diff --git a/requirements.txt b/requirements.dev.txt
similarity index 100%
rename from requirements.txt
rename to requirements.dev.txt
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29