title: execute hello world with flask "ImportError: No module named flask"
body: <p>I'm trying to use flask and python. I did a simple file named <code>hello.py</code>. tHis file contains this code:</p>
  
  <pre><code>from flask import Flask
  app = Flask(__name__)
  
  
  @app.route("/")
  def main():
      return "Welcome!"
  
  if __name__ == "__main__":
      app.run()
  </code></pre>
  
  <p>This is a simple hello world with flask. I want to execute it but actually, I have a problem. In the terminal, I typed <code>python hello.py</code> 
  and I get this error:</p>
  
  <pre><code>File "hello.py", line 1, in &lt;module&gt;
  from flask import Flask
  ImportError: No module named flask
  </code></pre>
  
  <p>Even that I installed flask globally.
  I understand that this is a basic question, but I'm stuck?</p>